From a1b72869cce823f06265fdd1ad1eca11244293bf Mon Sep 17 00:00:00 2001
From: Martin Goik <goik@hdm-stuttgart.de>
Date: Sun, 9 Jul 2017 12:20:48 +0200
Subject: [PATCH] New intro/exercises sections
---
Doc/Sd1/languageFundamentals.xml | 4767 +++++++++++++++---------------
1 file changed, 2397 insertions(+), 2370 deletions(-)
diff --git a/Doc/Sd1/languageFundamentals.xml b/Doc/Sd1/languageFundamentals.xml
index 37219722b..931a3c99e 100644
--- a/Doc/Sd1/languageFundamentals.xml
+++ b/Doc/Sd1/languageFundamentals.xml
@@ -11,1154 +11,1162 @@
xmlns:db="http://docbook.org/ns/docbook">
<title>Language Fundamentals</title>
- <section xml:id="sd1_fig_asciiAndUnicode">
- <title>Integer, <xref linkend="glo_ASCII"/> and <xref
- linkend="glo_unicode"/></title>
+ <section xml:id="sd1_sect_langFundamental_intro">
+ <title>Introduction</title>
- <para>We will 9IUD4Gus3PJlFG241X74mainly deal with computation machines.
- Having just mechanical devices at hand this still works:</para>
+ <section xml:id="sd1_fig_asciiAndUnicode">
+ <title>Integer, <xref linkend="glo_ASCII"/> and <xref
+ linkend="glo_unicode"/></title>
- <figure xml:id="sd1_fig_cashier">
- <title>Cash register</title>
+ <para>We will 9IUD4Gus3PJlFG241X74mainly deal with computation machines.
+ Having just mechanical devices at hand this still works:</para>
- <mediaobject>
- <imageobject>
- <imagedata fileref="Ref/LangFundament/cashRegister.png"/>
- </imageobject>
- </mediaobject>
- </figure>
+ <figure xml:id="sd1_fig_cashier">
+ <title>Cash register</title>
- <figure xml:id="sd1_fig_zuseZ3">
- <title>Zuse Z3</title>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="Ref/LangFundament/cashRegister.png"/>
+ </imageobject>
+ </mediaobject>
+ </figure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="Ref/LangFundament/zuseZ3.jpg"/>
- </imageobject>
- </mediaobject>
- </figure>
+ <figure xml:id="sd1_fig_zuseZ3">
+ <title>Zuse Z3</title>
- <figure xml:id="sd1_fig_eniac">
- <title>Eniac</title>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="Ref/LangFundament/zuseZ3.jpg"/>
+ </imageobject>
+ </mediaobject>
+ </figure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="Ref/LangFundament/eniac.jpg"/>
- </imageobject>
- </mediaobject>
- </figure>
+ <figure xml:id="sd1_fig_eniac">
+ <title>Eniac</title>
- <para>So far all machines being described are based on non-semiconductor
- technologies. Inventing the transistor in the fifties gave rise to a rapid
- development of microprocessor chips:</para>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="Ref/LangFundament/eniac.jpg"/>
+ </imageobject>
+ </mediaobject>
+ </figure>
- <figure xml:id="sd1_fig_microprocessors">
- <title>Microprocessor ICs</title>
+ <para>So far all machines being described are based on non-semiconductor
+ technologies. Inventing the transistor in the fifties gave rise to a
+ rapid development of microprocessor chips:</para>
- <mediaobject>
- <imageobject>
- <imagedata fileref="Ref/LangFundament/processors.svg"/>
- </imageobject>
- </mediaobject>
- </figure>
+ <figure xml:id="sd1_fig_microprocessors">
+ <title>Microprocessor ICs</title>
- <para>These sample devices differ heavily with respect to addressable
- memory, data size, supported arithmetic operations / speed and other
- features. We take a closer look to Zilog's Z80 processor:</para>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="Ref/LangFundament/processors.svg"/>
+ </imageobject>
+ </mediaobject>
+ </figure>
- <figure xml:id="sd1_fig_z80">
- <title>Zilog Z80 CPU</title>
+ <para>These sample devices differ heavily with respect to addressable
+ memory, data size, supported arithmetic operations / speed and other
+ features. We take a closer look to Zilog's Z80 processor:</para>
- <mediaobject>
- <imageobject>
- <imagedata fileref="Ref/LangFundament/z80DataBus.jpg"/>
- </imageobject>
- </mediaobject>
- </figure>
+ <figure xml:id="sd1_fig_z80">
+ <title>Zilog Z80 CPU</title>
- <para>Following technological advances processors have been categorized by
- the length the so called address- and data-bus:</para>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="Ref/LangFundament/z80DataBus.jpg"/>
+ </imageobject>
+ </mediaobject>
+ </figure>
- <figure xml:id="sd1_fig_adressDataBus">
- <title>Address and data bus sizes</title>
+ <para>Following technological advances processors have been categorized
+ by the length the so called address- and data-bus:</para>
- <informaltable border="1">
- <tr>
- <th>Processor</th>
+ <figure xml:id="sd1_fig_adressDataBus">
+ <title>Address and data bus sizes</title>
- <th>Year</th>
+ <informaltable border="1">
+ <tr>
+ <th>Processor</th>
- <th>Address size / Bit</th>
+ <th>Year</th>
- <th>Data size / Bit</th>
- </tr>
+ <th>Address size / Bit</th>
- <tr>
- <td>Intel 4004</td>
+ <th>Data size / Bit</th>
+ </tr>
- <td>1971</td>
+ <tr>
+ <td>Intel 4004</td>
- <td>12</td>
+ <td>1971</td>
- <td>4</td>
- </tr>
+ <td>12</td>
- <tr>
- <td>Zilog Z80</td>
+ <td>4</td>
+ </tr>
- <td>1976</td>
+ <tr>
+ <td>Zilog Z80</td>
- <td>16</td>
+ <td>1976</td>
- <td>8</td>
- </tr>
+ <td>16</td>
- <tr>
- <td>Motorola 68000</td>
+ <td>8</td>
+ </tr>
- <td>1980</td>
+ <tr>
+ <td>Motorola 68000</td>
- <td>24 / 32</td>
+ <td>1980</td>
- <td>16</td>
- </tr>
+ <td>24 / 32</td>
- <tr>
- <td>Motorola 68020</td>
+ <td>16</td>
+ </tr>
- <td>1984</td>
+ <tr>
+ <td>Motorola 68020</td>
- <td>32</td>
+ <td>1984</td>
- <td>32</td>
- </tr>
+ <td>32</td>
- <tr>
- <td>AMD Opteron</td>
+ <td>32</td>
+ </tr>
- <td>2003</td>
+ <tr>
+ <td>AMD Opteron</td>
- <td>64</td>
+ <td>2003</td>
- <td>64</td>
- </tr>
- </informaltable>
- </figure>
+ <td>64</td>
- <para>We remind the reader to the binary representation of signed integer
- values. Details will be discussed in your math lectures. Our first example
- features three bit 2-complement:</para>
+ <td>64</td>
+ </tr>
+ </informaltable>
+ </figure>
- <figure xml:id="sd1_fig_signed3bitIntDual">
- <title>Signed 3 bit integer representation</title>
+ <para>We remind the reader to the binary representation of signed
+ integer values. Details will be discussed in your math lectures. Our
+ first example features three bit 2-complement:</para>
- <mediaobject>
- <imageobject>
- <imagedata fileref="Ref/LangFundament/dualSigned3bit.svg"/>
- </imageobject>
- </mediaobject>
- </figure>
+ <figure xml:id="sd1_fig_signed3bitIntDual">
+ <title>Signed 3 bit integer representation</title>
- <para>Signed <code>byte</code> values are being represented
- accordingly:</para>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="Ref/LangFundament/dualSigned3bit.svg"/>
+ </imageobject>
+ </mediaobject>
+ </figure>
- <figure xml:id="sd1_fig_signedIntRepresentBinary">
- <title>Signed 8 bit integer binary representation</title>
+ <para>Signed <code>byte</code> values are being represented
+ accordingly:</para>
- <mediaobject>
- <imageobject>
- <imagedata fileref="Ref/LangFundament/dualSignedByte.svg"/>
- </imageobject>
- </mediaobject>
- </figure>
+ <figure xml:id="sd1_fig_signedIntRepresentBinary">
+ <title>Signed 8 bit integer binary representation</title>
- <para>Regarding language characters we start with one of the oldest and
- widespread character encoding schemes:</para>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="Ref/LangFundament/dualSignedByte.svg"/>
+ </imageobject>
+ </mediaobject>
+ </figure>
- <figure xml:id="sd1_fig_7bitASCII">
- <title>7-bit <xref linkend="glo_ASCII"/></title>
+ <para>Regarding language characters we start with one of the oldest and
+ widespread character encoding schemes:</para>
- <mediaobject>
- <imageobject>
- <imagedata fileref="Ref/LangFundament/ascii7bit.svg"/>
- </imageobject>
- </mediaobject>
- </figure>
+ <figure xml:id="sd1_fig_7bitASCII">
+ <title>7-bit <xref linkend="glo_ASCII"/></title>
- <para><xref linkend="glo_ASCII"/> by design is limited to US characters
- and does not include characters from non-English languages. Since <xref
- linkend="glo_ASCII"/> only uses seven bits we may a parity bit to form one
- byte per character:</para>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="Ref/LangFundament/ascii7bit.svg"/>
+ </imageobject>
+ </mediaobject>
+ </figure>
- <figure xml:id="sd1_fig_7bitASCII_andParity">
- <title>7-bit <xref linkend="glo_ASCII"/> with even parity bit</title>
+ <para><xref linkend="glo_ASCII"/> by design is limited to US characters
+ and does not include characters from non-English languages. Since <xref
+ linkend="glo_ASCII"/> only uses seven bits we may a parity bit to form
+ one byte per character:</para>
- <mediaobject>
- <imageobject>
- <imagedata fileref="Ref/LangFundament/ascii7bitEven.svg"/>
- </imageobject>
- </mediaobject>
- </figure>
+ <figure xml:id="sd1_fig_7bitASCII_andParity">
+ <title>7-bit <xref linkend="glo_ASCII"/> with even parity bit</title>
- <para>A byte's parity bit may instead be used for encoding non- <xref
- linkend="glo_ASCII"/> supplementary characters. One such example is the
- <link xlink:href="https://en.wikipedia.org/wiki/ISO/IEC_8859-1">ISO 8859-1
- (ISO Latin 1)</link> standard representing western European character
- sets:</para>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="Ref/LangFundament/ascii7bitEven.svg"/>
+ </imageobject>
+ </mediaobject>
+ </figure>
- <figure xml:id="sd1_fig_iso8859_1">
- <title><link
- xlink:href="https://en.wikipedia.org/wiki/ISO/IEC_8859-1">ISO Latin
- 1</link> encoding</title>
-
- <mediaobject>
- <imageobject>
- <imagedata fileref="Ref/LangFundament/iso8859_1.svg"/>
- </imageobject>
- </mediaobject>
- </figure>
-
- <para>Supporting additional languages comes at a price: We have to
- increase the number of bytes representing a single character:</para>
-
- <figure xml:id="sd1_fig_unicodeSample">
- <title>Some <xref linkend="glo_unicode"/> <link
- xlink:href="https://en.wikipedia.org/wiki/UTF-8">UTF-8</link>
- samples</title>
-
- <mediaobject>
- <imageobject>
- <imagedata fileref="Ref/LangFundament/unicode.svg"/>
- </imageobject>
- </mediaobject>
- </figure>
-
- <para>Notice the representation's differing byte count: <link
- xlink:href="https://en.wikipedia.org/wiki/UTF-8">UTF-8</link> <xref
- linkend="glo_unicode"/> encoding allows for one-, two-, three- and four-
- byte encodings. See <quote
- xlink:href="https://betterexplained.com/articles/unicode">Unicode and
- You</quote> for further details.</para>
- </section>
+ <para>A byte's parity bit may instead be used for encoding non- <xref
+ linkend="glo_ASCII"/> supplementary characters. One such example is the
+ <link xlink:href="https://en.wikipedia.org/wiki/ISO/IEC_8859-1">ISO
+ 8859-1 (ISO Latin 1)</link> standard representing western European
+ character sets:</para>
+
+ <figure xml:id="sd1_fig_iso8859_1">
+ <title><link
+ xlink:href="https://en.wikipedia.org/wiki/ISO/IEC_8859-1">ISO Latin
+ 1</link> encoding</title>
+
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="Ref/LangFundament/iso8859_1.svg"/>
+ </imageobject>
+ </mediaobject>
+ </figure>
+
+ <para>Supporting additional languages comes at a price: We have to
+ increase the number of bytes representing a single character:</para>
+
+ <figure xml:id="sd1_fig_unicodeSample">
+ <title>Some <xref linkend="glo_unicode"/> <link
+ xlink:href="https://en.wikipedia.org/wiki/UTF-8">UTF-8</link>
+ samples</title>
+
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="Ref/LangFundament/unicode.svg"/>
+ </imageobject>
+ </mediaobject>
+ </figure>
+
+ <para>Notice the representation's differing byte count: <link
+ xlink:href="https://en.wikipedia.org/wiki/UTF-8">UTF-8</link> <xref
+ linkend="glo_unicode"/> encoding allows for one-, two-, three- and four-
+ byte encodings. See <quote
+ xlink:href="https://betterexplained.com/articles/unicode">Unicode and
+ You</quote> for further details.</para>
+ </section>
- <section xml:id="sd1_sect_variables">
- <title>Variables</title>
+ <section xml:id="sd1_sect_variables">
+ <title>Variables</title>
- <para>Variables are convenient handles for accessing memory. We don't need
- to mess with memory addresses:</para>
+ <para>Variables are convenient handles for accessing memory. We don't
+ need to mess with memory addresses:</para>
- <figure xml:id="sd1_fig_varMemoryHandle">
- <title>Handle to memory</title>
+ <figure xml:id="sd1_fig_varMemoryHandle">
+ <title>Handle to memory</title>
- <mediaobject>
- <imageobject>
- <imagedata fileref="Ref/LangFundament/variableToMemory.svg"/>
- </imageobject>
- </mediaobject>
- </figure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="Ref/LangFundament/variableToMemory.svg"/>
+ </imageobject>
+ </mediaobject>
+ </figure>
- <para>Declaring a variable requires a type name like <code>double</code>
- and an identifier:</para>
+ <para>Declaring a variable requires a type name like <code>double</code>
+ and an identifier:</para>
- <figure xml:id="sd1_fig_varDeclare">
- <title>Variable declaration</title>
+ <figure xml:id="sd1_fig_varDeclare">
+ <title>Variable declaration</title>
- <programlisting language="java">double pi;</programlisting>
- </figure>
+ <programlisting language="java">double pi;</programlisting>
+ </figure>
- <para>We may assign values to variables or build expressions like <code>pi
- * 2.0 * 2.0</code> :</para>
+ <para>We may assign values to variables or build expressions like
+ <code>pi * 2.0 * 2.0</code> :</para>
- <figure xml:id="sd1_fig_varDeclareAndUse">
- <title>Declare and use</title>
+ <figure xml:id="sd1_fig_varDeclareAndUse">
+ <title>Declare and use</title>
- <programlisting language="java">double pi; // Declaration
+ <programlisting language="java">double pi; // Declaration
...
pi = 3.1415926; // Value assignment
// Area of circle having radius 2.0
System.out.println(pi * 2.0. * 2.0);</programlisting>
- </figure>
+ </figure>
- <figure xml:id="sd1_fig_varDeclareInit">
- <title>Declaration and initialization</title>
+ <figure xml:id="sd1_fig_varDeclareInit">
+ <title>Declaration and initialization</title>
- <glosslist>
- <glossentry>
- <glossterm>Separate declaration and initialization</glossterm>
+ <glosslist>
+ <glossentry>
+ <glossterm>Separate declaration and initialization</glossterm>
- <glossdef>
- <programlisting language="java">double pi; // Declaration of variable pi
+ <glossdef>
+ <programlisting language="java">double pi; // Declaration of variable pi
...
pi = 3.1415926; // Value assignment</programlisting>
- </glossdef>
- </glossentry>
+ </glossdef>
+ </glossentry>
- <glossentry>
- <glossterm>Combined declaration and initialization</glossterm>
+ <glossentry>
+ <glossterm>Combined declaration and initialization</glossterm>
- <glossdef>
- <programlisting language="java">double pi = 3.1415926;</programlisting>
- </glossdef>
- </glossentry>
- </glosslist>
- </figure>
+ <glossdef>
+ <programlisting language="java">double pi = 3.1415926;</programlisting>
+ </glossdef>
+ </glossentry>
+ </glosslist>
+ </figure>
- <figure xml:id="sd1_fig_varMultiple">
- <title>Multiple variables of same type</title>
+ <figure xml:id="sd1_fig_varMultiple">
+ <title>Multiple variables of same type</title>
- <programlisting language="java">int a;
+ <programlisting language="java">int a;
int b = 22;
int c;</programlisting>
- <para>is equivalent to either of:</para>
+ <para>is equivalent to either of:</para>
- <informaltable border="1">
- <tr>
- <th>Compact</th>
+ <informaltable border="1">
+ <tr>
+ <th>Compact</th>
- <th>Multiple lines</th>
- </tr>
+ <th>Multiple lines</th>
+ </tr>
- <tr>
- <td valign="top"><programlisting language="java">int a, b = 22, c; </programlisting></td>
+ <tr>
+ <td valign="top"><programlisting language="java">int a, b = 22, c; </programlisting></td>
- <td valign="top"><programlisting language="java">int a,
+ <td valign="top"><programlisting language="java">int a,
b = 22,
c;</programlisting></td>
- </tr>
- </informaltable>
- </figure>
-
- <figure xml:id="sd1_fig_varNameConventions">
- <title>Variable naming conventions</title>
-
- <itemizedlist>
- <listitem>
- <para>Start with a small letter like <code>africa</code> rather than
- <code>Africa</code>.</para>
- </listitem>
-
- <listitem>
- <para>Use <quote>camel case</quote> e.g.
- <code>myFirstCode</code>.</para>
-
- <mediaobject>
- <imageobject>
- <imagedata fileref="Ref/LangFundament/camelCase.svg"/>
- </imageobject>
- </mediaobject>
- </listitem>
-
- <listitem>
- <para>Do not start with <code>_</code> or <code>$</code>.</para>
- </listitem>
- </itemizedlist>
- </figure>
-
- <figure xml:id="sd1_fig_varFinal">
- <title>Constants</title>
-
- <programlisting language="java">final double pi = 3.1415926;
+ </tr>
+ </informaltable>
+ </figure>
+
+ <figure xml:id="sd1_fig_varNameConventions">
+ <title>Variable naming conventions</title>
+
+ <itemizedlist>
+ <listitem>
+ <para>Start with a small letter like <code>africa</code> rather
+ than <code>Africa</code>.</para>
+ </listitem>
+
+ <listitem>
+ <para>Use <quote>camel case</quote> e.g.
+ <code>myFirstCode</code>.</para>
+
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="Ref/LangFundament/camelCase.svg"/>
+ </imageobject>
+ </mediaobject>
+ </listitem>
+
+ <listitem>
+ <para>Do not start with <code>_</code> or <code>$</code>.</para>
+ </listitem>
+ </itemizedlist>
+ </figure>
+
+ <figure xml:id="sd1_fig_varFinal">
+ <title>Constants</title>
+
+ <programlisting language="java">final double pi = 3.1415926;
...
pi = 1.0; // Compile time error: Constant cannot be modified</programlisting>
- </figure>
-
- <figure xml:id="sd1_fig_legalVariableName">
- <title>Variable names</title>
+ </figure>
- <para>A variable</para>
+ <figure xml:id="sd1_fig_legalVariableName">
+ <title>Variable names</title>
- <informaltable border="1">
- <tr>
- <td><itemizedlist>
- <listitem>
- <para>Starts with a letter</para>
- </listitem>
-
- <listitem>
- <para>May be followed by letters or digits</para>
- </listitem>
-
- <listitem>
- <para>Must not match:</para>
-
- <itemizedlist>
- <listitem>
- <para>a <xref linkend="glo_Java"/> keyword</para>
- </listitem>
+ <para>A variable</para>
- <listitem>
- <para>a boolean literal</para>
- </listitem>
+ <informaltable border="1">
+ <tr>
+ <td><itemizedlist>
+ <listitem>
+ <para>Starts with a letter</para>
+ </listitem>
- <listitem>
- <para>The <code>null</code> literal</para>
- </listitem>
- </itemizedlist>
- </listitem>
- </itemizedlist></td>
+ <listitem>
+ <para>May be followed by letters or digits</para>
+ </listitem>
- <td><glosslist>
- <glossentry>
- <glossterm>Legal</glossterm>
+ <listitem>
+ <para>Must not match:</para>
- <glossdef>
<itemizedlist>
<listitem>
- <para>$test</para>
+ <para>a <xref linkend="glo_Java"/> keyword</para>
</listitem>
<listitem>
- <para>count</para>
+ <para>a boolean literal</para>
</listitem>
<listitem>
- <para>blue</para>
+ <para>The <code>null</code> literal</para>
</listitem>
</itemizedlist>
- </glossdef>
- </glossentry>
+ </listitem>
+ </itemizedlist></td>
- <glossentry>
- <glossterm>Illegal</glossterm>
+ <td><glosslist>
+ <glossentry>
+ <glossterm>Legal</glossterm>
- <glossdef>
- <itemizedlist>
- <listitem>
- <para>2sad</para>
- </listitem>
+ <glossdef>
+ <itemizedlist>
+ <listitem>
+ <para>$test</para>
+ </listitem>
+
+ <listitem>
+ <para>count</para>
+ </listitem>
+
+ <listitem>
+ <para>blue</para>
+ </listitem>
+ </itemizedlist>
+ </glossdef>
+ </glossentry>
- <listitem>
- <para>switch</para>
- </listitem>
+ <glossentry>
+ <glossterm>Illegal</glossterm>
- <listitem>
- <para>true</para>
- </listitem>
- </itemizedlist>
- </glossdef>
- </glossentry>
- </glosslist></td>
- </tr>
- </informaltable>
- </figure>
+ <glossdef>
+ <itemizedlist>
+ <listitem>
+ <para>2sad</para>
+ </listitem>
+
+ <listitem>
+ <para>switch</para>
+ </listitem>
+
+ <listitem>
+ <para>true</para>
+ </listitem>
+ </itemizedlist>
+ </glossdef>
+ </glossentry>
+ </glosslist></td>
+ </tr>
+ </informaltable>
+ </figure>
- <figure xml:id="sd1_fig_varCaseSensitive">
- <title>Case sensitivity</title>
+ <figure xml:id="sd1_fig_varCaseSensitive">
+ <title>Case sensitivity</title>
- <para>Variable names are case sensitive:</para>
+ <para>Variable names are case sensitive:</para>
- <programlisting language="java">int count = 32;
+ <programlisting language="java">int count = 32;
int Count = 44;
System.out.println(count + ":" + Count); // This yields "32:44"</programlisting>
- </figure>
+ </figure>
- <figure xml:id="sd1_fig_varDeclareBeforeUse">
- <title>Declare before use</title>
+ <figure xml:id="sd1_fig_varDeclareBeforeUse">
+ <title>Declare before use</title>
- <glosslist>
- <glossentry>
- <glossterm>Correct:</glossterm>
+ <glosslist>
+ <glossentry>
+ <glossterm>Correct:</glossterm>
- <glossdef>
- <programlisting language="java">double f;
+ <glossdef>
+ <programlisting language="java">double f;
f = -4.55;</programlisting>
- </glossdef>
- </glossentry>
+ </glossdef>
+ </glossentry>
- <glossentry>
- <glossterm>Wrong</glossterm>
+ <glossentry>
+ <glossterm>Wrong</glossterm>
- <glossdef>
- <programlisting language="java">f = -4.55;
+ <glossdef>
+ <programlisting language="java">f = -4.55;
double f;</programlisting>
- </glossdef>
- </glossentry>
- </glosslist>
- </figure>
+ </glossdef>
+ </glossentry>
+ </glosslist>
+ </figure>
- <figure xml:id="sd1_fig_typeSafety">
- <title>Type safety</title>
+ <figure xml:id="sd1_fig_typeSafety">
+ <title>Type safety</title>
- <programlisting language="java">int i = 2;
+ <programlisting language="java">int i = 2;
int j = i; // o.K.: Assigning int to int
boolean b = true;
i = b; // Error: int and boolean are incompatible types
i = "Hello"; // Even worse: Assigning a String to an int</programlisting>
- </figure>
+ </figure>
+
+ <para><xref linkend="glo_Java"/> provides meta information on
+ types:</para>
+
+ <figure xml:id="sd1_fig_intTypeMaxMin">
+ <title>Maximum and minimum values</title>
+
+ <informaltable border="1">
+ <tr>
+ <th>Type</th>
+
+ <th>Bytes</th>
+
+ <th>Min value</th>
+
+ <th>Max value</th>
+ </tr>
+
+ <tr>
+ <td>byte</td>
+
+ <td><link
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/java/lang/Byte.html#BYTES">1</link></td>
+
+ <td><link
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Byte.MIN_VALUE"><inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:mo>-</m:mo>
+
+ <m:msup>
+ <m:mi>2</m:mi>
+
+ <m:mi>7</m:mi>
+ </m:msup>
+ </m:mrow>
+ </m:math>
+ </inlineequation></link></td>
+
+ <td><link
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Byte.MAX_VALUE"><inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:msup>
+ <m:mi>2</m:mi>
+
+ <m:mi>7</m:mi>
+ </m:msup>
+
+ <m:mo>-</m:mo>
+
+ <m:mi>1</m:mi>
+ </m:mrow>
+ </m:math>
+ </inlineequation></link></td>
+ </tr>
+
+ <tr>
+ <td>char</td>
+
+ <td><link
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/java/lang/Byte.html#BYTES">2</link></td>
+
+ <td>0</td>
+
+ <td><link
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Character.MAX_VALUE"><inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:msup>
+ <m:mi>2</m:mi>
+
+ <m:mi>16</m:mi>
+ </m:msup>
+
+ <m:mo>-</m:mo>
+
+ <m:mi>1</m:mi>
+ </m:mrow>
+ </m:math>
+ </inlineequation></link></td>
+ </tr>
+
+ <tr>
+ <td>short</td>
+
+ <td><link
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Short.BYTES">2</link></td>
+
+ <td><link
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Short.MIN_VALUE"><inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:mo>-</m:mo>
+
+ <m:msup>
+ <m:mi>2</m:mi>
+
+ <m:mi>15</m:mi>
+ </m:msup>
+ </m:mrow>
+ </m:math>
+ </inlineequation></link></td>
+
+ <td><link
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Short.MAX_VALUE"><inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:msup>
+ <m:mi>2</m:mi>
+
+ <m:mi>15</m:mi>
+ </m:msup>
- <para><xref linkend="glo_Java"/> provides meta information on
- types:</para>
+ <m:mo>-</m:mo>
- <figure xml:id="sd1_fig_intTypeMaxMin">
- <title>Maximum and minimum values</title>
+ <m:mi>1</m:mi>
+ </m:mrow>
+ </m:math>
+ </inlineequation></link></td>
+ </tr>
- <informaltable border="1">
- <tr>
- <th>Type</th>
+ <tr>
+ <td>int</td>
- <th>Bytes</th>
+ <td><link
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Integer.BYTES">4</link></td>
- <th>Min value</th>
+ <td><link
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Integer.MIN_VALUE"><inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:mo>-</m:mo>
- <th>Max value</th>
- </tr>
+ <m:msup>
+ <m:mi>2</m:mi>
- <tr>
- <td>byte</td>
+ <m:mi>31</m:mi>
+ </m:msup>
+ </m:mrow>
+ </m:math>
+ </inlineequation></link></td>
+
+ <td><link
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Integer.MAX_VALUE"><inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:msup>
+ <m:mi>2</m:mi>
- <td><link
- xlink:href="https://docs.oracle.com/javase/8/docs/api/java/lang/Byte.html#BYTES">1</link></td>
+ <m:mi>31</m:mi>
+ </m:msup>
- <td><link
- xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Byte.MIN_VALUE"><inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:mo>-</m:mo>
+ <m:mo>-</m:mo>
- <m:msup>
- <m:mi>2</m:mi>
+ <m:mi>1</m:mi>
+ </m:mrow>
+ </m:math>
+ </inlineequation></link></td>
+ </tr>
- <m:mi>7</m:mi>
- </m:msup>
- </m:mrow>
- </m:math>
- </inlineequation></link></td>
+ <tr>
+ <td>long</td>
- <td><link
- xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Byte.MAX_VALUE"><inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:msup>
- <m:mi>2</m:mi>
+ <td><link
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Long.BYTES">8</link></td>
- <m:mi>7</m:mi>
- </m:msup>
+ <td><link
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Long.MIN_VALUE"><inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:mo>-</m:mo>
- <m:mo>-</m:mo>
+ <m:msup>
+ <m:mi>2</m:mi>
- <m:mi>1</m:mi>
- </m:mrow>
- </m:math>
- </inlineequation></link></td>
- </tr>
+ <m:mi>63</m:mi>
+ </m:msup>
+ </m:mrow>
+ </m:math>
+ </inlineequation></link></td>
+
+ <td><link
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Long.MAX_VALUE"><inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:msup>
+ <m:mi>2</m:mi>
- <tr>
- <td>char</td>
+ <m:mi>63</m:mi>
+ </m:msup>
- <td><link
- xlink:href="https://docs.oracle.com/javase/8/docs/api/java/lang/Byte.html#BYTES">2</link></td>
+ <m:mo>-</m:mo>
- <td>0</td>
+ <m:mi>1</m:mi>
+ </m:mrow>
+ </m:math>
+ </inlineequation></link></td>
+ </tr>
+ </informaltable>
+ </figure>
- <td><link
- xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Character.MAX_VALUE"><inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:msup>
- <m:mi>2</m:mi>
+ <figure xml:id="sd1_fig_variableCategories">
+ <title>Two categories of variables</title>
- <m:mi>16</m:mi>
- </m:msup>
+ <glosslist>
+ <glossentry>
+ <glossterm>Primitive type</glossterm>
- <m:mo>-</m:mo>
+ <glossdef>
+ <programlisting language="java">int a = -15;</programlisting>
- <m:mi>1</m:mi>
- </m:mrow>
- </m:math>
- </inlineequation></link></td>
- </tr>
+ <para>Possible types: All eight primitive <xref
+ linkend="glo_Java"/> types.</para>
+ </glossdef>
+ </glossentry>
- <tr>
- <td>short</td>
+ <glossentry>
+ <glossterm>Reference type</glossterm>
- <td><link
- xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Short.BYTES">2</link></td>
+ <glossdef>
+ <programlisting language="java">GpsPosition start = new GpsPosition(48.7758, 9.1829);</programlisting>
- <td><link
- xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Short.MIN_VALUE"><inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:mo>-</m:mo>
+ <para>Possible types: Arbitrary built in or user defined
+ classes.</para>
+ </glossdef>
+ </glossentry>
+ </glosslist>
+ </figure>
- <m:msup>
- <m:mi>2</m:mi>
+ <figure xml:id="sd1_fig_refTypeVariants">
+ <title>Reference type variants</title>
- <m:mi>15</m:mi>
- </m:msup>
- </m:mrow>
- </m:math>
- </inlineequation></link></td>
-
- <td><link
- xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Short.MAX_VALUE"><inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:msup>
- <m:mi>2</m:mi>
-
- <m:mi>15</m:mi>
- </m:msup>
-
- <m:mo>-</m:mo>
-
- <m:mi>1</m:mi>
- </m:mrow>
- </m:math>
- </inlineequation></link></td>
- </tr>
-
- <tr>
- <td>int</td>
-
- <td><link
- xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Integer.BYTES">4</link></td>
-
- <td><link
- xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Integer.MIN_VALUE"><inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:mo>-</m:mo>
-
- <m:msup>
- <m:mi>2</m:mi>
-
- <m:mi>31</m:mi>
- </m:msup>
- </m:mrow>
- </m:math>
- </inlineequation></link></td>
-
- <td><link
- xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Integer.MAX_VALUE"><inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:msup>
- <m:mi>2</m:mi>
-
- <m:mi>31</m:mi>
- </m:msup>
-
- <m:mo>-</m:mo>
-
- <m:mi>1</m:mi>
- </m:mrow>
- </m:math>
- </inlineequation></link></td>
- </tr>
-
- <tr>
- <td>long</td>
-
- <td><link
- xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Long.BYTES">8</link></td>
-
- <td><link
- xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Long.MIN_VALUE"><inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:mo>-</m:mo>
-
- <m:msup>
- <m:mi>2</m:mi>
-
- <m:mi>63</m:mi>
- </m:msup>
- </m:mrow>
- </m:math>
- </inlineequation></link></td>
-
- <td><link
- xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Long.MAX_VALUE"><inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:msup>
- <m:mi>2</m:mi>
-
- <m:mi>63</m:mi>
- </m:msup>
-
- <m:mo>-</m:mo>
-
- <m:mi>1</m:mi>
- </m:mrow>
- </m:math>
- </inlineequation></link></td>
- </tr>
- </informaltable>
- </figure>
-
- <figure xml:id="sd1_fig_variableCategories">
- <title>Two categories of variables</title>
-
- <glosslist>
- <glossentry>
- <glossterm>Primitive type</glossterm>
-
- <glossdef>
- <programlisting language="java">int a = -15;</programlisting>
-
- <para>Possible types: All eight primitive <xref
- linkend="glo_Java"/> types.</para>
- </glossdef>
- </glossentry>
-
- <glossentry>
- <glossterm>Reference type</glossterm>
-
- <glossdef>
- <programlisting language="java">GpsPosition start = new GpsPosition(48.7758, 9.1829);</programlisting>
-
- <para>Possible types: Arbitrary built in or user defined
- classes.</para>
- </glossdef>
- </glossentry>
- </glosslist>
- </figure>
-
- <figure xml:id="sd1_fig_refTypeVariants">
- <title>Reference type variants</title>
-
- <programlisting language="java">GpsPosition start = new GpsPosition(48.7758, 9.1829);
+ <programlisting language="java">GpsPosition start = new GpsPosition(48.7758, 9.1829);
String name = "Simon";
LocalDate birtday = LocalDate.of(1990, Month.JULY, 5);</programlisting>
- </figure>
- </section>
+ </figure>
+ </section>
- <section xml:id="sd1_sect_literals">
- <title>Literals</title>
+ <section xml:id="sd1_sect_literals">
+ <title>Literals</title>
- <figure xml:id="sd1_fig_literal2memory">
- <title><code>float</code> and <code>double</code></title>
+ <figure xml:id="sd1_fig_literal2memory">
+ <title><code>float</code> and <code>double</code></title>
- <mediaobject>
- <imageobject>
- <imagedata fileref="Ref/LangFundament/literalToMemory.svg"/>
- </imageobject>
- </mediaobject>
- </figure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="Ref/LangFundament/literalToMemory.svg"/>
+ </imageobject>
+ </mediaobject>
+ </figure>
- <figure xml:id="sd1_fig_equivalentIntRepresentations">
- <title>Four ways representing 35</title>
+ <figure xml:id="sd1_fig_equivalentIntRepresentations">
+ <title>Four ways representing 35</title>
- <informaltable border="1">
- <tr>
- <th>Code</th>
+ <informaltable border="1">
+ <tr>
+ <th>Code</th>
- <th>Result</th>
- </tr>
+ <th>Result</th>
+ </tr>
- <tr>
- <td><programlisting language="java">System.out.println("Decimal "+ <emphasis
- role="bold">35</emphasis>);
+ <tr>
+ <td><programlisting language="java">System.out.println("Decimal "+ <emphasis
+ role="bold">35</emphasis>);
System.out.println("Binary " + <emphasis role="bold">0b10_0011</emphasis>);
System.out.println("Hex " + <emphasis role="bold">0x23</emphasis>);
System.out.println("Octal " + <emphasis role="bold">043</emphasis>); </programlisting></td>
- <td><programlisting language="none">Decimal 35
+ <td><programlisting language="none">Decimal 35
Binary 35
Hex 35
Octal 35</programlisting></td>
- </tr>
- </informaltable>
- </figure>
+ </tr>
+ </informaltable>
+ </figure>
+ </section>
</section>
- <section xml:id="sd1_sect_arithmeticLimitations">
- <title>Arithmetic limitations</title>
+ <section xml:id="sd1_sect_langFundamental_exercises">
+ <title>Exercises</title>
+
+ <section xml:id="sd1_sect_arithmeticLimitations">
+ <title>Arithmetic limitations</title>
- <para>Expect the unexpected:</para>
+ <para>Expect the unexpected:</para>
- <figure xml:id="sd1_fig_byteLitteralAssign">
- <title>Strange things</title>
+ <figure xml:id="sd1_fig_byteLitteralAssign">
+ <title>Strange things</title>
- <programlisting language="java">byte count = 91; // o.K.
+ <programlisting language="java">byte count = 91; // o.K.
byte points = 130; // Compile error: Incompatible types
// Required: byte Found: int</programlisting>
- </figure>
+ </figure>
- <figure xml:id="sd1_fig_byteOverflow">
- <title>Funny things</title>
+ <figure xml:id="sd1_fig_byteOverflow">
+ <title>Funny things</title>
- <programlisting language="java">int count = 2147483647;
+ <programlisting language="java">int count = 2147483647;
int points = 2147483647;
int sum = count + points;
System.out.println("Sum = " + sum);</programlisting>
- <para>Result:</para>
+ <para>Result:</para>
- <informaltable border="1">
- <tr>
- <td><programlisting language="none">Sum = -2</programlisting></td>
+ <informaltable border="1">
+ <tr>
+ <td><programlisting language="none">Sum = -2</programlisting></td>
- <td><programlisting language="none"> 01111111_11111111_11111111_11111111
+ <td><programlisting language="none"> 01111111_11111111_11111111_11111111
+ 01111111_11111111_11111111_11111111
_____________________________________
11111111_11111111_11111111_11111110</programlisting></td>
- </tr>
- </informaltable>
- </figure>
+ </tr>
+ </informaltable>
+ </figure>
- <para>Why not using float / double in favour of bounded <code>byte</code>,
- <code>short</code>, <code>int</code>, <code>long</code> for
- arithmetics?</para>
+ <para>Why not using float / double in favour of bounded
+ <code>byte</code>, <code>short</code>, <code>int</code>,
+ <code>long</code> for arithmetics?</para>
- <figure xml:id="sd1_fig_floatPrecision">
- <title>Limited precision</title>
+ <figure xml:id="sd1_fig_floatPrecision">
+ <title>Limited precision</title>
- <programlisting language="java">float float2Power31 = Integer.MAX_VALUE + 1f;
+ <programlisting language="java">float float2Power31 = Integer.MAX_VALUE + 1f;
float floatDoubleMAX_VALUE = 2 * float2Power31* float2Power31 - 1f; // 2^63 - 1
System.out.format( " Float value: %f\n", floatDoubleMAX_VALUE);
System.out.println("Expected value: " + Long.MAX_VALUE);</programlisting>
- <para>Result:</para>
+ <para>Result:</para>
- <programlisting language="none"> Float value: 9223372036854776000.000000
+ <programlisting language="none"> Float value: 9223372036854776000.000000
Expected value: 9223372036854775807
</programlisting>
- </figure>
- </section>
-
- <section xml:id="sw1LegalVariableName">
- <title>Legal variable names</title>
+ </figure>
+ </section>
- <qandaset defaultlabel="qanda" xml:id="sw1QandaLegalVarNames">
+ <section xml:id="sw1LegalVariableName">
<title>Legal variable names</title>
- <qandadiv>
- <qandaentry>
- <question>
- <para>Which of the following names are legal variable names?
- Complete the following table and explain your decision with
- respect to the <quote
- xlink:href="https://proquest.safaribooksonline.com/9780992133047/toc4_html_3">variables</quote>
- section.</para>
+ <qandaset defaultlabel="qanda" xml:id="sw1QandaLegalVarNames">
+ <title>Legal variable names</title>
+
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>Which of the following names are legal variable names?
+ Complete the following table and explain your decision with
+ respect to the <quote
+ xlink:href="https://proquest.safaribooksonline.com/9780992133047/toc4_html_3">variables</quote>
+ section.</para>
- <informaltable border="1">
- <colgroup width="19%"/>
+ <informaltable border="1">
+ <colgroup width="19%"/>
- <colgroup width="10%"/>
+ <colgroup width="10%"/>
- <colgroup width="71%"/>
+ <colgroup width="71%"/>
- <tr>
- <th>Identifier</th>
+ <tr>
+ <th>Identifier</th>
- <th>is legal? (yes / no)</th>
+ <th>is legal? (yes / no)</th>
- <th>Explanation / remark</th>
- </tr>
+ <th>Explanation / remark</th>
+ </tr>
- <tr>
- <td><code>for</code></td>
+ <tr>
+ <td><code>for</code></td>
- <td/>
+ <td/>
- <td/>
- </tr>
+ <td/>
+ </tr>
- <tr>
- <td><code>sum_of_data</code></td>
+ <tr>
+ <td><code>sum_of_data</code></td>
- <td/>
+ <td/>
- <td/>
- </tr>
+ <td/>
+ </tr>
- <tr>
- <td><code>sumOfData</code></td>
+ <tr>
+ <td><code>sumOfData</code></td>
- <td/>
+ <td/>
- <td/>
- </tr>
+ <td/>
+ </tr>
- <tr>
- <td><code>first-name</code></td>
+ <tr>
+ <td><code>first-name</code></td>
- <td/>
+ <td/>
- <td/>
- </tr>
+ <td/>
+ </tr>
- <tr>
- <td><code>ABC</code></td>
+ <tr>
+ <td><code>ABC</code></td>
- <td/>
+ <td/>
- <td/>
- </tr>
+ <td/>
+ </tr>
- <tr>
- <td><code>42isThesolution</code></td>
+ <tr>
+ <td><code>42isThesolution</code></td>
- <td/>
+ <td/>
- <td/>
- </tr>
+ <td/>
+ </tr>
- <tr>
- <td><code>println</code></td>
+ <tr>
+ <td><code>println</code></td>
- <td/>
+ <td/>
- <td/>
- </tr>
+ <td/>
+ </tr>
- <tr>
- <td><code>B4</code></td>
+ <tr>
+ <td><code>B4</code></td>
- <td/>
+ <td/>
- <td/>
- </tr>
+ <td/>
+ </tr>
- <tr>
- <td><code>AnnualSalary</code></td>
+ <tr>
+ <td><code>AnnualSalary</code></td>
- <td/>
+ <td/>
- <td/>
- </tr>
+ <td/>
+ </tr>
- <tr>
- <td><code>"hello"</code></td>
+ <tr>
+ <td><code>"hello"</code></td>
- <td/>
+ <td/>
- <td/>
- </tr>
+ <td/>
+ </tr>
- <tr>
- <td><code>_average </code></td>
+ <tr>
+ <td><code>_average </code></td>
- <td/>
+ <td/>
- <td/>
- </tr>
+ <td/>
+ </tr>
- <tr>
- <td><code>ανδÏος</code></td>
+ <tr>
+ <td><code>ανδÏος</code></td>
- <td/>
+ <td/>
- <td/>
- </tr>
+ <td/>
+ </tr>
- <tr>
- <td><code>$sum </code></td>
+ <tr>
+ <td><code>$sum </code></td>
- <td/>
+ <td/>
- <td/>
- </tr>
- </informaltable>
+ <td/>
+ </tr>
+ </informaltable>
- <tip>
- <para>You may want to prepare a simple <xref
- linkend="glo_Java"/> program testing the above names.</para>
- </tip>
- </question>
+ <tip>
+ <para>You may want to prepare a simple <xref
+ linkend="glo_Java"/> program testing the above names.</para>
+ </tip>
+ </question>
- <answer>
- <para>We may write a small <xref linkend="glo_Java"/>
- program:</para>
+ <answer>
+ <para>We may write a small <xref linkend="glo_Java"/>
+ program:</para>
- <programlisting language="java">public static void main(String[] args) {
+ <programlisting language="java">public static void main(String[] args) {
int 42isThesolution = 6; // <emphasis role="bold">Syntax error on token "42", delete this token</emphasis>
}</programlisting>
- <para>Unfortunately the error explanation is not too helpful with
- respect to <xref linkend="glo_Java"/> beginners. It does not
- immediately point towards an illegal identifier problem. One
- indication of a sound compiler is its ability to provide
- meaningful, self explanatory error messages.</para>
+ <para>Unfortunately the error explanation is not too helpful
+ with respect to <xref linkend="glo_Java"/> beginners. It does
+ not immediately point towards an illegal identifier problem. One
+ indication of a sound compiler is its ability to provide
+ meaningful, self explanatory error messages.</para>
- <informaltable border="1">
- <colgroup width="19%"/>
+ <informaltable border="1">
+ <colgroup width="19%"/>
- <colgroup width="10%"/>
+ <colgroup width="10%"/>
- <colgroup width="71%"/>
+ <colgroup width="71%"/>
- <tr>
- <th>Identifier</th>
+ <tr>
+ <th>Identifier</th>
- <th>is legal? (yes / no)</th>
+ <th>is legal? (yes / no)</th>
- <th>Explanation / remark</th>
- </tr>
+ <th>Explanation / remark</th>
+ </tr>
- <tr>
- <td><code>for</code></td>
+ <tr>
+ <td><code>for</code></td>
- <td>no</td>
+ <td>no</td>
- <td><quote>for</quote> is a Java keyword.</td>
- </tr>
+ <td><quote>for</quote> is a Java keyword.</td>
+ </tr>
- <tr>
- <td><code>sum_of_data</code></td>
+ <tr>
+ <td><code>sum_of_data</code></td>
- <td>yes</td>
+ <td>yes</td>
- <td>-</td>
- </tr>
+ <td>-</td>
+ </tr>
- <tr>
- <td><code>sumOfData</code></td>
+ <tr>
+ <td><code>sumOfData</code></td>
- <td>yes</td>
+ <td>yes</td>
- <td>-</td>
- </tr>
+ <td>-</td>
+ </tr>
- <tr>
- <td><code>first-name</code></td>
+ <tr>
+ <td><code>first-name</code></td>
- <td>no</td>
+ <td>no</td>
- <td>Operators like <quote>-</quote> or <quote>+</quote> must
- not appear in variable names.</td>
- </tr>
+ <td>Operators like <quote>-</quote> or <quote>+</quote> must
+ not appear in variable names.</td>
+ </tr>
- <tr>
- <td><code>ABC</code></td>
+ <tr>
+ <td><code>ABC</code></td>
- <td>yes</td>
+ <td>yes</td>
- <td>Best practices: Discouraged variable name, non-constant
- variables should start with lowercase letters.</td>
- </tr>
+ <td>Best practices: Discouraged variable name, non-constant
+ variables should start with lowercase letters.</td>
+ </tr>
- <tr>
- <td><code>42isThesolution</code></td>
+ <tr>
+ <td><code>42isThesolution</code></td>
- <td>no</td>
+ <td>no</td>
- <td>Identifiers must not start with a number.</td>
- </tr>
+ <td>Identifiers must not start with a number.</td>
+ </tr>
- <tr>
- <td><code>println</code></td>
+ <tr>
+ <td><code>println</code></td>
- <td>yes</td>
+ <td>yes</td>
- <td><code>println</code> is a method of
- <code>System.out.println(...)</code> but is no <xref
- linkend="glo_Java"/> keyword.</td>
- </tr>
+ <td><code>println</code> is a method of
+ <code>System.out.println(...)</code> but is no <xref
+ linkend="glo_Java"/> keyword.</td>
+ </tr>
- <tr>
- <td><code>B4</code></td>
+ <tr>
+ <td><code>B4</code></td>
- <td>yes</td>
+ <td>yes</td>
- <td>Best practices: Discouraged variable name, non-constant
- variables should start with lowercase letters.</td>
- </tr>
+ <td>Best practices: Discouraged variable name, non-constant
+ variables should start with lowercase letters.</td>
+ </tr>
- <tr>
- <td><code>AnnualSalary</code></td>
+ <tr>
+ <td><code>AnnualSalary</code></td>
- <td>yes</td>
+ <td>yes</td>
- <td>Best practices: Legal but discouraged variable name:
- Non-constant variables should start with lowercase
- letters.</td>
- </tr>
+ <td>Best practices: Legal but discouraged variable name:
+ Non-constant variables should start with lowercase
+ letters.</td>
+ </tr>
- <tr>
- <td><code>"hello"</code></td>
+ <tr>
+ <td><code>"hello"</code></td>
- <td>no</td>
+ <td>no</td>
- <td>String delimiters must not be part of an identifier.</td>
- </tr>
+ <td>String delimiters must not be part of an
+ identifier.</td>
+ </tr>
- <tr>
- <td><code>_average </code></td>
+ <tr>
+ <td><code>_average </code></td>
- <td>yes</td>
+ <td>yes</td>
- <td>Best practices: Should be reserved for system code.</td>
- </tr>
+ <td>Best practices: Should be reserved for system code.</td>
+ </tr>
- <tr>
- <td><code>ανδÏος</code></td>
+ <tr>
+ <td><code>ανδÏος</code></td>
- <td>yes</td>
+ <td>yes</td>
- <td>Perfectly legal Greek <orgname>Unicode</orgname>
- characters.</td>
- </tr>
+ <td>Perfectly legal Greek <orgname>Unicode</orgname>
+ characters.</td>
+ </tr>
- <tr>
- <td><code>$sum </code></td>
+ <tr>
+ <td><code>$sum </code></td>
- <td>yes</td>
+ <td>yes</td>
- <td>Best practices: Using the <quote>$</quote> sign should be
- reserved for system code.</td>
- </tr>
- </informaltable>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
- </section>
+ <td>Best practices: Using the <quote>$</quote> sign should
+ be reserved for system code.</td>
+ </tr>
+ </informaltable>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+ </section>
- <section xml:id="sw1IntegerLiterals">
- <title>Integer value literals</title>
+ <section xml:id="sw1IntegerLiterals">
+ <title>Integer value literals</title>
- <section xml:id="sd1SectBinaryIntLiteral">
- <title>Binary literals</title>
+ <section xml:id="sd1SectBinaryIntLiteral">
+ <title>Binary literals</title>
- <qandaset defaultlabel="qanda" xml:id="sd1QandaBinaryIntLiteral">
- <qandadiv>
- <qandaentry>
- <question>
- <orderedlist>
- <listitem>
- <para>Using the decimal system to represent integer values
- we tend to ignore other important numbering systems. Write
- an application which prints the decimal value of
- <inlineequation>
- <m:math display="inline">
- <m:msub>
- <m:mi>1110100100</m:mi>
+ <qandaset defaultlabel="qanda" xml:id="sd1QandaBinaryIntLiteral">
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <orderedlist>
+ <listitem>
+ <para>Using the decimal system to represent integer values
+ we tend to ignore other important numbering systems. Write
+ an application which prints the decimal value of
+ <inlineequation>
+ <m:math display="inline">
+ <m:msub>
+ <m:mi>1110100100</m:mi>
- <m:mi>2</m:mi>
- </m:msub>
- </m:math>
- </inlineequation> by writing the former as a binary int
- literal. Verify the printed value by an independent
- calculation.</para>
- </listitem>
+ <m:mi>2</m:mi>
+ </m:msub>
+ </m:math>
+ </inlineequation> by writing the former as a binary int
+ literal. Verify the printed value by an independent
+ calculation.</para>
+ </listitem>
- <listitem>
- <para>Construct a second binary literal representing a
- negative value of your choice.</para>
+ <listitem>
+ <para>Construct a second binary literal representing a
+ negative value of your choice.</para>
- <tip>
- <para>An <code>int</code> is being represented by four
- bytes in <xref linkend="glo_Java"/>.</para>
- </tip>
- </listitem>
- </orderedlist>
- </question>
+ <tip>
+ <para>An <code>int</code> is being represented by four
+ bytes in <xref linkend="glo_Java"/>.</para>
+ </tip>
+ </listitem>
+ </orderedlist>
+ </question>
- <answer>
- <orderedlist>
- <listitem>
- <programlisting language="java">public static void main(String[] args) {
+ <answer>
+ <orderedlist>
+ <listitem>
+ <programlisting language="java">public static void main(String[] args) {
System.out.println(" Binary:" + 0B11_10100100);
System.out.println("Decimal:" + (512
@@ -1168,161 +1176,162 @@ Expected value: 9223372036854775807
+ 4));
}</programlisting>
- <para>This yields:</para>
+ <para>This yields:</para>
- <programlisting language="none"> Binary:932
+ <programlisting language="none"> Binary:932
Decimal:932</programlisting>
- </listitem>
+ </listitem>
- <listitem>
- <para>A negative value in <link
- xlink:href="https://en.wikipedia.org/wiki/Two's_complement#firstHeading">Two's
- complement</link> representation starts with a
- <quote>1</quote> at its highest bit. Binary literals in
- <xref linkend="glo_Java"/> represent <code>int</code>
- values. An <code>int</code> in <xref linkend="glo_Java"/>
- uses 4 bytes and thus occupies 4 x 8=32 bits. Therefore
- choosing a negative value is a simple task: Start with
- <quote>1</quote> and let it follow by 32 - 1 = 31 random bit
- values:</para>
-
- <programlisting language="java">public static void main(String[] args) {
+ <listitem>
+ <para>A negative value in <link
+ xlink:href="https://en.wikipedia.org/wiki/Two's_complement#firstHeading">Two's
+ complement</link> representation starts with a
+ <quote>1</quote> at its highest bit. Binary literals in
+ <xref linkend="glo_Java"/> represent <code>int</code>
+ values. An <code>int</code> in <xref linkend="glo_Java"/>
+ uses 4 bytes and thus occupies 4 x 8=32 bits. Therefore
+ choosing a negative value is a simple task: Start with
+ <quote>1</quote> and let it follow by 32 - 1 = 31 random
+ bit values:</para>
+
+ <programlisting language="java">public static void main(String[] args) {
System.out.println(0B10000000_00111001_01101001_01110100);
}</programlisting>
- </listitem>
- </orderedlist>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
- </section>
-
- <section xml:id="sd1SectBracesInPrintln">
- <title>Why using braces inside <code>System.out.println(...)</code>
- ?</title>
-
- <qandaset defaultlabel="qanda" xml:id="sd1QandaBracesInPrintln">
- <qandadiv>
- <qandaentry>
- <question>
- <para>Solution <xref linkend="sd1SectBinaryIntLiteral"/>
- contains:</para>
-
- <programlisting language="java">...
+ </listitem>
+ </orderedlist>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+ </section>
+
+ <section xml:id="sd1SectBracesInPrintln">
+ <title>Why using braces inside <code>System.out.println(...)</code>
+ ?</title>
+
+ <qandaset defaultlabel="qanda" xml:id="sd1QandaBracesInPrintln">
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>Solution <xref linkend="sd1SectBinaryIntLiteral"/>
+ contains:</para>
+
+ <programlisting language="java">...
System.out.println("Decimal:" + (512 +
256 +
128 +
32 +
4)); ...</programlisting>
- <para>Why are the <quote>inner</quote> braces immediately
- preceding 512 and following 4 are being required?</para>
+ <para>Why are the <quote>inner</quote> braces immediately
+ preceding 512 and following 4 are being required?</para>
- <tip>
- <itemizedlist>
- <listitem>
- <para>Execute the above code omitting the
- <quote>inner</quote> braces.</para>
- </listitem>
+ <tip>
+ <itemizedlist>
+ <listitem>
+ <para>Execute the above code omitting the
+ <quote>inner</quote> braces.</para>
+ </listitem>
- <listitem>
- <para>Read about the <quote>+</quote> operator's role e.g.
- in <code>System.out.println("Some" + "
- string").</code></para>
- </listitem>
- </itemizedlist>
- </tip>
- </question>
+ <listitem>
+ <para>Read about the <quote>+</quote> operator's role
+ e.g. in <code>System.out.println("Some" + "
+ string").</code></para>
+ </listitem>
+ </itemizedlist>
+ </tip>
+ </question>
- <answer>
- <para>We start omitting the <quote>inner</quote> braces:</para>
+ <answer>
+ <para>We start omitting the <quote>inner</quote>
+ braces:</para>
- <programlisting language="java">...
+ <programlisting language="java">...
System.out.println("Decimal:" + 512 +
256 +
128 +
32 +
4); ...</programlisting>
- <para>This results in the following output:</para>
+ <para>This results in the following output:</para>
- <programlisting language="none">...
+ <programlisting language="none">...
Decimal:512256128324</programlisting>
- <para>The numbers are being treated as strings rather than
- integer values The above code is equivalent to:</para>
+ <para>The numbers are being treated as strings rather than
+ integer values The above code is equivalent to:</para>
- <programlisting language="java">...
+ <programlisting language="java">...
System.out.println("Decimal:" + "512" +
"256" +
"128" +
"32" +
"4"); ...</programlisting>
- <para>The <quote>+</quote> operator between two strings defines
- their concatenation. So all six components get joined into a
- single result string.</para>
+ <para>The <quote>+</quote> operator between two strings
+ defines their concatenation. So all six components get joined
+ into a single result string.</para>
- <para>Supplying additional inner braces defines an expression
- (512 + 256 + 128 + 32 + 4) solely involving integer values. In
- this context each <quote>+</quote> operator effects the usual
- integer arithmetic:</para>
+ <para>Supplying additional inner braces defines an expression
+ (512 + 256 + 128 + 32 + 4) solely involving integer values. In
+ this context each <quote>+</quote> operator effects the usual
+ integer arithmetic:</para>
- <programlisting language="java">...
+ <programlisting language="java">...
System.out.println("Decimal:" +<co linkends="sd1ListingPlusOpDuplicate-1"
- xml:id="sd1ListingPlusOpDuplicate-1-co"/> (512 +<co
- linkends="sd1ListingPlusOpDuplicate-2"
- xml:id="sd1ListingPlusOpDuplicate-2-co"/>
+ xml:id="sd1ListingPlusOpDuplicate-1-co"/> (512 +<co
+ linkends="sd1ListingPlusOpDuplicate-2"
+ xml:id="sd1ListingPlusOpDuplicate-2-co"/>
256 +<co
- linkends="sd1ListingPlusOpDuplicate-2"
- xml:id="sd1ListingPlusOpDuplicate-3-co"/>
+ linkends="sd1ListingPlusOpDuplicate-2"
+ xml:id="sd1ListingPlusOpDuplicate-3-co"/>
128 +<co
- linkends="sd1ListingPlusOpDuplicate-2"
- xml:id="sd1ListingPlusOpDuplicate-4-co"/>
+ linkends="sd1ListingPlusOpDuplicate-2"
+ xml:id="sd1ListingPlusOpDuplicate-4-co"/>
32 +<co
- linkends="sd1ListingPlusOpDuplicate-2"
- xml:id="sd1ListingPlusOpDuplicate-5-co"/>
+ linkends="sd1ListingPlusOpDuplicate-2"
+ xml:id="sd1ListingPlusOpDuplicate-5-co"/>
4)); ...</programlisting>
- <calloutlist>
- <callout arearefs="sd1ListingPlusOpDuplicate-1-co"
- xml:id="sd1ListingPlusOpDuplicate-1">
- <para><quote>+</quote> operator concatenating the two
- strings <code>"Decimal:"</code> and
- <code>"932"</code>.</para>
- </callout>
-
- <callout arearefs="sd1ListingPlusOpDuplicate-2-co sd1ListingPlusOpDuplicate-3-co sd1ListingPlusOpDuplicate-4-co sd1ListingPlusOpDuplicate-5-co"
- xml:id="sd1ListingPlusOpDuplicate-2">
- <para><quote>+</quote> operators computing the integer sum
- of 512, 256, 128, 32 and 4 yielding a value of 932. This
- value subsequently gets transformed into the String
- <code>"932"</code> in order to be compatible with the
- preceding <code>"Decimal:"</code> string.</para>
- </callout>
- </calloutlist>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
- </section>
-
- <section xml:id="sd1_sect_poorMansAscii">
- <title>Poor mans ASCII table</title>
-
- <qandaset defaultlabel="qanda" xml:id="sd1_qanda_poorMansAscii">
- <qandadiv>
- <qandaentry>
- <question>
- <para>We want to construct a list of <link
- xlink:href="http://www.rapidtables.com/code/text/ascii-table.htm#print">printable
- ASCII characters</link>. Write a <xref linkend="glo_Java"/>
- application by starting just from from character literals
- <code>' '</code>, <code>'!'</code>, <code>'"'</code>,
- <code>'#'</code> and so on to show their corresponding decimal
- values. The intended output is:</para>
-
- <programlisting language="none"> : 32
+ <calloutlist>
+ <callout arearefs="sd1ListingPlusOpDuplicate-1-co"
+ xml:id="sd1ListingPlusOpDuplicate-1">
+ <para><quote>+</quote> operator concatenating the two
+ strings <code>"Decimal:"</code> and
+ <code>"932"</code>.</para>
+ </callout>
+
+ <callout arearefs="sd1ListingPlusOpDuplicate-2-co sd1ListingPlusOpDuplicate-3-co sd1ListingPlusOpDuplicate-4-co sd1ListingPlusOpDuplicate-5-co"
+ xml:id="sd1ListingPlusOpDuplicate-2">
+ <para><quote>+</quote> operators computing the integer sum
+ of 512, 256, 128, 32 and 4 yielding a value of 932. This
+ value subsequently gets transformed into the String
+ <code>"932"</code> in order to be compatible with the
+ preceding <code>"Decimal:"</code> string.</para>
+ </callout>
+ </calloutlist>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+ </section>
+
+ <section xml:id="sd1_sect_poorMansAscii">
+ <title>Poor mans ASCII table</title>
+
+ <qandaset defaultlabel="qanda" xml:id="sd1_qanda_poorMansAscii">
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>We want to construct a list of <link
+ xlink:href="http://www.rapidtables.com/code/text/ascii-table.htm#print">printable
+ ASCII characters</link>. Write a <xref linkend="glo_Java"/>
+ application by starting just from from character literals
+ <code>' '</code>, <code>'!'</code>, <code>'"'</code>,
+ <code>'#'</code> and so on to show their corresponding decimal
+ values. The intended output is:</para>
+
+ <programlisting language="none"> : 32
!: 33
": 34
#: 35
@@ -1330,20 +1339,21 @@ $: 36
%: 37
&: 38</programlisting>
- <para>Notice the empty space being represented by decimal
- 32.</para>
+ <para>Notice the empty space being represented by decimal
+ 32.</para>
- <tip>
- <para>A <code>char</code> value being represented by two bytes
- may be easily assigned to an <code>int</code> variable.</para>
- </tip>
- </question>
+ <tip>
+ <para>A <code>char</code> value being represented by two
+ bytes may be easily assigned to an <code>int</code>
+ variable.</para>
+ </tip>
+ </question>
- <answer>
- <para>Since <code>char</code> values may be assigned to
- <code>int</code> variables we may code:</para>
+ <answer>
+ <para>Since <code>char</code> values may be assigned to
+ <code>int</code> variables we may code:</para>
- <programlisting language="java">{
+ <programlisting language="java">{
char c = ' '; // space
int value = c;
System.out.println(c + ": " + value);
@@ -1360,10 +1370,10 @@ $: 36
}
...</programlisting>
- <para>Using an explicit type conversion from char to int (a so
- called cast) yields an identical result:</para>
+ <para>Using an explicit type conversion from char to int (a so
+ called cast) yields an identical result:</para>
- <programlisting language="java">System.out.println(' ' + ": " + ((int) ' '));
+ <programlisting language="java">System.out.println(' ' + ": " + ((int) ' '));
System.out.println('!' + ": " + ((int) '!'));
System.out.println('"' + ": " + ((int) '"'));
System.out.println('#' + ": " + ((int) '#'));
@@ -1371,35 +1381,36 @@ System.out.println('$' + ": " + ((int) '$'));
System.out.println('%' + ": " + ((int) '%'));
System.out.println('&' + ": " + ((int) '&'));
...</programlisting>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
- </section>
-
- <section xml:id="sw1SectHexadecimalLiterals">
- <title>Hexadecimal literals</title>
-
- <para>As you may know the <xref linkend="glo_RGB"/> color model uses
- triplets of numbers to define color value components representing
- intensities of its three base colors <foreignphrase><emphasis
- role="bold">R</emphasis>ed</foreignphrase>, <foreignphrase><emphasis
- role="bold">G</emphasis>reen</foreignphrase> and
- <foreignphrase><emphasis role="bold">B</emphasis>lue</foreignphrase>.
- The component values range from 0 to 255, the latter defining maximum
- intensity.</para>
-
- <para>The color <quote>red</quote> for example is being represented by
- (255, 0, 0). So the red component has maximum intensity while blue and
- green are zero.</para>
-
- <para>It is however common to use <link
- xlink:href="http://www.december.com/html/spec/color16codes.html">hexadecimal
- in favour of decimal values</link>. Thus the same color
- <quote>red</quote> in the subsequent HTML example's heading font is now
- being represented by <emphasis role="bold">(FF,0,0)</emphasis>:</para>
-
- <programlisting language="html"><!DOCTYPE html>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+ </section>
+
+ <section xml:id="sw1SectHexadecimalLiterals">
+ <title>Hexadecimal literals</title>
+
+ <para>As you may know the <xref linkend="glo_RGB"/> color model uses
+ triplets of numbers to define color value components representing
+ intensities of its three base colors <foreignphrase><emphasis
+ role="bold">R</emphasis>ed</foreignphrase>, <foreignphrase><emphasis
+ role="bold">G</emphasis>reen</foreignphrase> and
+ <foreignphrase><emphasis role="bold">B</emphasis>lue</foreignphrase>.
+ The component values range from 0 to 255, the latter defining maximum
+ intensity.</para>
+
+ <para>The color <quote>red</quote> for example is being represented by
+ (255, 0, 0). So the red component has maximum intensity while blue and
+ green are zero.</para>
+
+ <para>It is however common to use <link
+ xlink:href="http://www.december.com/html/spec/color16codes.html">hexadecimal
+ in favour of decimal values</link>. Thus the same color
+ <quote>red</quote> in the subsequent HTML example's heading font is
+ now being represented by <emphasis
+ role="bold">(FF,0,0)</emphasis>:</para>
+
+ <programlisting language="html"><!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>A simple color example</title>
@@ -1408,453 +1419,458 @@ System.out.println('&' + ": " + ((int) '&'));
<body><h1 style="<emphasis role="bold">color: #FF0000;</emphasis>">My heading</h1></body>
</html></programlisting>
- <qandaset defaultlabel="qanda" xml:id="sw1QandaIntByBinary">
- <title>Integer values by binary representations</title>
+ <qandaset defaultlabel="qanda" xml:id="sw1QandaIntByBinary">
+ <title>Integer values by binary representations</title>
+
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>Write a program printing the hexadecimal representation
+ <inlineequation>
+ <m:math display="inline">
+ <m:msub>
+ <m:mi>C0</m:mi>
+
+ <m:mi>16</m:mi>
+ </m:msub>
+ </m:math>
+ </inlineequation> as a decimal value.</para>
+
+ <para>Complete the following code by assigning the hexadecimal
+ value <inlineequation>
+ <m:math display="inline">
+ <m:msub>
+ <m:mi>C0</m:mi>
+
+ <m:mi>16</m:mi>
+ </m:msub>
+ </m:math>
+ </inlineequation> (The <quote>silver</quote> color's all
+ three component's intensity in <uri
+ xlink:href="http://www.december.com/html/spec/color16codes.html">http://www.december.com/html/spec/color16codes.html</uri>)
+ to get the output in decimal representation.</para>
+
+ <programlisting language="java">public static void main(String[] args) {
+ short intensity = ...;
+
+ System.out.println(intensity);
+}</programlisting>
- <qandadiv>
- <qandaentry>
- <question>
- <para>Write a program printing the hexadecimal representation
- <inlineequation>
- <m:math display="inline">
- <m:msub>
- <m:mi>C0</m:mi>
-
- <m:mi>16</m:mi>
- </m:msub>
- </m:math>
- </inlineequation> as a decimal value.</para>
-
- <para>Complete the following code by assigning the hexadecimal
- value <inlineequation>
- <m:math display="inline">
- <m:msub>
- <m:mi>C0</m:mi>
-
- <m:mi>16</m:mi>
- </m:msub>
- </m:math>
- </inlineequation> (The <quote>silver</quote> color's all three
- component's intensity in <uri
- xlink:href="http://www.december.com/html/spec/color16codes.html">http://www.december.com/html/spec/color16codes.html</uri>)
- to get the output in decimal representation.</para>
-
- <programlisting language="java">public static void main(String[] args) {
- short intensity = ...;
-
- System.out.println(intensity);
-}</programlisting>
+ <tip>
+ <para>You may want to consider the <quote
+ xlink:href="https://proquest.safaribooksonline.com/9780992133047/toc6_html_2">Literals</quote>
+ section of <xref linkend="bib_Kurniawan2015"/> learning
+ about hexadecimal integer value representation.</para>
+ </tip>
+ </question>
- <tip>
- <para>You may want to consider the <quote
- xlink:href="https://proquest.safaribooksonline.com/9780992133047/toc6_html_2">Literals</quote>
- section of <xref linkend="bib_Kurniawan2015"/> learning about
- hexadecimal integer value representation.</para>
- </tip>
- </question>
+ <answer>
+ <para>The solution is straightforward:</para>
- <answer>
- <para>The solution is straightforward:</para>
-
- <programlisting language="java"> public static void main(String[] args) {
+ <programlisting language="java"> public static void main(String[] args) {
short intensity = 0xC0;
System.out.println(intensity);
}</programlisting>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
-
- <qandaset defaultlabel="qanda" xml:id="sw1QandaIntLimitShort">
- <title>Testing the limits, part 2 (Difficult)</title>
-
- <qandadiv>
- <qandaentry>
- <question>
- <para>A careful programmer is worried whether a short variable
- is <emphasis role="bold">always</emphasis> large enough to hold
- color intensity values ranging from 0 to 255. Give an answer
- being based on the <link
- xlink:href="https://docs.oracle.com/javase/specs/jls/se8/html/jls-4.html#jls-4.2.1">specification</link>
- and not just by try-and-error.</para>
-
- <para>The programmer tries to adopt the <link
- linkend="sw1QandaMaxMinInt">related int example</link>
- accordingly:</para>
-
- <programlisting language="java">short minumum = 0B10000000_00000000,
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+
+ <qandaset defaultlabel="qanda" xml:id="sw1QandaIntLimitShort">
+ <title>Testing the limits, part 2 (Difficult)</title>
+
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>A careful programmer is worried whether a short variable
+ is <emphasis role="bold">always</emphasis> large enough to
+ hold color intensity values ranging from 0 to 255. Give an
+ answer being based on the <link
+ xlink:href="https://docs.oracle.com/javase/specs/jls/se8/html/jls-4.html#jls-4.2.1">specification</link>
+ and not just by try-and-error.</para>
+
+ <para>The programmer tries to adopt the <link
+ linkend="sw1QandaMaxMinInt">related int example</link>
+ accordingly:</para>
+
+ <programlisting language="java">short minumum = 0B10000000_00000000,
maximum = 0B01111111_11111111;
System.out.println("Minimum short value:" + minumum);
System.out.println("Maximum short value:" + maximum);
</programlisting>
- <para>Our programmer is baffled since:</para>
-
- <itemizedlist>
- <listitem>
- <para>The first assignment <code language="java">minumum =
- 0B10000000_00000000</code> is being flagged as a compile
- time error:</para>
+ <para>Our programmer is baffled since:</para>
- <para><computeroutput>Type mismatch: cannot convert from int
- to short</computeroutput></para>
- </listitem>
-
- <listitem>
- <para>On contrary the second assignment <code
- language="java">maximum = 0B01111111_11111111</code> gets
- smoothly accepted.</para>
- </listitem>
- </itemizedlist>
+ <itemizedlist>
+ <listitem>
+ <para>The first assignment <code language="java">minumum =
+ 0B10000000_00000000</code> is being flagged as a compile
+ time error:</para>
- <tip>
- <para>Which integer literals types do exist according to the
- <xref linkend="glo_Java"/> <link
- xlink:href="https://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-3.10.1">standard</link>?</para>
- </tip>
- </question>
+ <para><computeroutput>Type mismatch: cannot convert from
+ int to short</computeroutput></para>
+ </listitem>
- <answer>
- <para>Since variables of type <code>short</code> are being
- represented by to bytes their range is <inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:mo>[</m:mo>
+ <listitem>
+ <para>On contrary the second assignment <code
+ language="java">maximum = 0B01111111_11111111</code> gets
+ smoothly accepted.</para>
+ </listitem>
+ </itemizedlist>
+ <tip>
+ <para>Which integer literals types do exist according to the
+ <xref linkend="glo_Java"/> <link
+ xlink:href="https://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-3.10.1">standard</link>?</para>
+ </tip>
+ </question>
+
+ <answer>
+ <para>Since variables of type <code>short</code> are being
+ represented by to bytes their range is <inlineequation>
+ <m:math display="inline">
<m:mrow>
- <m:mrow>
- <m:mo>-</m:mo>
-
- <m:msup>
- <m:mi>2</m:mi>
-
- <m:mi>15</m:mi>
- </m:msup>
- </m:mrow>
-
- <m:mo>,</m:mo>
+ <m:mo>[</m:mo>
<m:mrow>
- <m:msup>
- <m:mi>2</m:mi>
+ <m:mrow>
+ <m:mo>-</m:mo>
- <m:mi>15</m:mi>
- </m:msup>
-
- <m:mo>-</m:mo>
+ <m:msup>
+ <m:mi>2</m:mi>
- <m:mi>1</m:mi>
- </m:mrow>
- </m:mrow>
+ <m:mi>15</m:mi>
+ </m:msup>
+ </m:mrow>
- <m:mo>]</m:mo>
- </m:mrow>
- </m:math>
- </inlineequation>. Thus intensity values ranging from 0 to 255
- will be easily accommodated.</para>
+ <m:mo>,</m:mo>
- <para>The second question is more difficult to explain: The
- <xref linkend="glo_Java"/> standard does define <code>int</code>
- literals. It does however not define <code>short</code> (or
- <code>byte</code>) literals.</para>
+ <m:mrow>
+ <m:msup>
+ <m:mi>2</m:mi>
- <para>Thus the 0B01111111_11111111 literal will be treated as an
- <code>int</code> value being compatible with a
- <code>short</code> variable and is thus assignable.</para>
+ <m:mi>15</m:mi>
+ </m:msup>
- <para>On the contrary the binary value
- <code>10000000_00000000</code> evaluates to <inlineequation>
- <m:math display="inline">
- <m:msup>
- <m:mn>2</m:mn>
+ <m:mo>-</m:mo>
- <m:mi>15</m:mi>
- </m:msup>
- </m:math>
- </inlineequation> (equal to 32768) exceeding a two-byte short
- variable's upper limit.</para>
-
- <para>Even worse: A <code>short</code> variable containing
- binary <code>10000000_00000000</code> due to its two byte <link
- xlink:href="https://en.wikipedia.org/wiki/Two's_complement#firstHeading">Two's
- complement</link> representation has got a value <inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:mo>-</m:mo>
+ <m:mi>1</m:mi>
+ </m:mrow>
+ </m:mrow>
+ <m:mo>]</m:mo>
+ </m:mrow>
+ </m:math>
+ </inlineequation>. Thus intensity values ranging from 0 to
+ 255 will be easily accommodated.</para>
+
+ <para>The second question is more difficult to explain: The
+ <xref linkend="glo_Java"/> standard does define
+ <code>int</code> literals. It does however not define
+ <code>short</code> (or <code>byte</code>) literals.</para>
+
+ <para>Thus the 0B01111111_11111111 literal will be treated as
+ an <code>int</code> value being compatible with a
+ <code>short</code> variable and is thus assignable.</para>
+
+ <para>On the contrary the binary value
+ <code>10000000_00000000</code> evaluates to <inlineequation>
+ <m:math display="inline">
<m:msup>
<m:mn>2</m:mn>
<m:mi>15</m:mi>
</m:msup>
- </m:mrow>
- </m:math>
- </inlineequation> (or -32768).</para>
-
- <para>In order to avoid this error we need an explicit type
- conversion (a so called cast):</para>
-
- <programlisting language="java">short minumum = (short) 0B10000000_00000000;</programlisting>
-
- <para>Since a <code>short</code> variable's range is
- <inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:mo>[</m:mo>
+ </m:math>
+ </inlineequation> (equal to 32768) exceeding a two-byte
+ short variable's upper limit.</para>
+ <para>Even worse: A <code>short</code> variable containing
+ binary <code>10000000_00000000</code> due to its two byte
+ <link
+ xlink:href="https://en.wikipedia.org/wiki/Two's_complement#firstHeading">Two's
+ complement</link> representation has got a value
+ <inlineequation>
+ <m:math display="inline">
<m:mrow>
- <m:mrow>
- <m:mo>-</m:mo>
-
- <m:msup>
- <m:mi>2</m:mi>
-
- <m:mi>15</m:mi>
- </m:msup>
- </m:mrow>
-
- <m:mo>,</m:mo>
-
- <m:mrow>
- <m:msup>
- <m:mi>2</m:mi>
-
- <m:mi>15</m:mi>
- </m:msup>
+ <m:mo>-</m:mo>
- <m:mo>-</m:mo>
+ <m:msup>
+ <m:mn>2</m:mn>
- <m:mi>1</m:mi>
- </m:mrow>
+ <m:mi>15</m:mi>
+ </m:msup>
</m:mrow>
+ </m:math>
+ </inlineequation> (or -32768).</para>
- <m:mo>]</m:mo>
- </m:mrow>
- </m:math>
- </inlineequation> we may as well use a unary minus sign
- instead:</para>
+ <para>In order to avoid this error we need an explicit type
+ conversion (a so called cast):</para>
- <programlisting language="java">short minumum = -0B10000000_00000000;</programlisting>
+ <programlisting language="java">short minumum = (short) 0B10000000_00000000;</programlisting>
- <para>Both variants are syntactically correct and will thus
- compile. However they are likely not being intended by our
- programmer.</para>
+ <para>Since a <code>short</code> variable's range is
+ <inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:mo>[</m:mo>
- <para>The error in the first place is probably assigning a value
- of <inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:mo>+</m:mo>
+ <m:mrow>
+ <m:mrow>
+ <m:mo>-</m:mo>
- <m:msup>
- <m:mi>2</m:mi>
+ <m:msup>
+ <m:mi>2</m:mi>
- <m:mi>15</m:mi>
- </m:msup>
- </m:mrow>
- </m:math>
- </inlineequation> to a <code>short</code> variable at
- all.</para>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
- </section>
+ <m:mi>15</m:mi>
+ </m:msup>
+ </m:mrow>
- <section xml:id="sd1_sect_exerciseEmoticons">
- <title><xref linkend="glo_unicode"/> and emoticons</title>
+ <m:mo>,</m:mo>
- <qandaset defaultlabel="qanda" xml:id="sd1_qanda_exerciseEmoticons">
- <qandadiv>
- <qandaentry>
- <question>
- <para>Referring to <xref linkend="sd1_fig_unicodeSample"/> we
- may use a corresponding <link
- xlink:href="https://en.wikibooks.org/wiki/Java_Programming/Literals#Character_Literals">character
- literal</link>:</para>
+ <m:mrow>
+ <m:msup>
+ <m:mi>2</m:mi>
- <programlisting language="java">final char arabicChar = 'ڜ'; // A <link
- xlink:href="https://en.wikibooks.org/wiki/Java_Programming/Literals#Character_Literals">character literal</link>
-System.out.println("Character: " + arabicChar);</programlisting>
+ <m:mi>15</m:mi>
+ </m:msup>
- <para>Execution yields the expected output. On contrary the
- following code snippet using the smiley instead does not even
- compile:</para>
+ <m:mo>-</m:mo>
- <mediaobject>
- <imageobject>
- <imagedata fileref="Ref/LangFundament/emoticonInvalidCharacterConstant.png"/>
- </imageobject>
- </mediaobject>
+ <m:mi>1</m:mi>
+ </m:mrow>
+ </m:mrow>
- <para>Explain the underlying problem.</para>
+ <m:mo>]</m:mo>
+ </m:mrow>
+ </m:math>
+ </inlineequation> we may as well use a unary minus sign
+ instead:</para>
- <tip>
- <para>Consider the number of bytes being allocated for
- <code>char</code> values in <xref linkend="glo_Java"/>.</para>
- </tip>
- </question>
+ <programlisting language="java">short minumum = -0B10000000_00000000;</programlisting>
- <answer>
- <para>According to the <link
- xlink:href="https://en.wikipedia.org/wiki/Arabic_(Unicode_block)#Block">Arabic
- block</link> table the code point of <code>'ڜ'</code> is U+069C
- having a decimal equivalent of 1692.</para>
-
- <para><xref linkend="glo_Java"/> uses two bytes equivalent to 16
- bits for representing positive <code>char</code> values. Thus
- the largest representable code point value is <inlineequation>
- <m:math display="inline">
- <m:mrow>
+ <para>Both variants are syntactically correct and will thus
+ compile. However they are likely not being intended by our
+ programmer.</para>
+
+ <para>The error in the first place is probably assigning a
+ value of <inlineequation>
+ <m:math display="inline">
<m:mrow>
+ <m:mo>+</m:mo>
+
<m:msup>
<m:mi>2</m:mi>
- <m:mi>16</m:mi>
+ <m:mi>15</m:mi>
</m:msup>
-
- <m:mo>-</m:mo>
-
- <m:mi>1</m:mi>
</m:mrow>
+ </m:math>
+ </inlineequation> to a <code>short</code> variable at
+ all.</para>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+ </section>
+
+ <section xml:id="sd1_sect_exerciseEmoticons">
+ <title><xref linkend="glo_unicode"/> and emoticons</title>
+
+ <qandaset defaultlabel="qanda" xml:id="sd1_qanda_exerciseEmoticons">
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>Referring to <xref linkend="sd1_fig_unicodeSample"/> we
+ may use a corresponding <link
+ xlink:href="https://en.wikibooks.org/wiki/Java_Programming/Literals#Character_Literals">character
+ literal</link>:</para>
+
+ <programlisting language="java">final char arabicChar = 'ڜ'; // A <link
+ xlink:href="https://en.wikibooks.org/wiki/Java_Programming/Literals#Character_Literals">character literal</link>
+System.out.println("Character: " + arabicChar);</programlisting>
- <m:mo>=</m:mo>
+ <para>Execution yields the expected output. On contrary the
+ following code snippet using the smiley instead does not even
+ compile:</para>
+
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="Ref/LangFundament/emoticonInvalidCharacterConstant.png"/>
+ </imageobject>
+ </mediaobject>
+
+ <para>Explain the underlying problem.</para>
+
+ <tip>
+ <para>Consider the number of bytes being allocated for
+ <code>char</code> values in <xref
+ linkend="glo_Java"/>.</para>
+ </tip>
+ </question>
+
+ <answer>
+ <para>According to the <link
+ xlink:href="https://en.wikipedia.org/wiki/Arabic_(Unicode_block)#Block">Arabic
+ block</link> table the code point of <code>'ڜ'</code> is
+ U+069C having a decimal equivalent of 1692.</para>
+
+ <para><xref linkend="glo_Java"/> uses two bytes equivalent to
+ 16 bits for representing positive <code>char</code> values.
+ Thus the largest representable code point value is
+ <inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:mrow>
+ <m:msup>
+ <m:mi>2</m:mi>
- <m:mi>65535</m:mi>
- </m:mrow>
- </m:math>
- </inlineequation>. So <code>'ڜ'</code> fits well into this
- range.</para>
+ <m:mi>16</m:mi>
+ </m:msup>
- <para>According to the <link
- xlink:href="https://en.wikipedia.org/wiki/Emoticons_(Unicode_block)">Emoticons
- table</link> the smiley's code point value is U+1F60E being
- equivalent to 128526 decimal. This exceeds the limit of 65535
- and thus prohibits the character literal in question.</para>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
- </section>
+ <m:mo>-</m:mo>
- <section xml:id="sd1SectIntMinMax">
- <title>An <code>int</code>'s minimum and maximum value</title>
+ <m:mi>1</m:mi>
+ </m:mrow>
- <qandaset defaultlabel="qanda" xml:id="sw1QandaMaxMinInt">
- <qandadiv>
- <qandaentry>
- <question>
- <para>In this exercise we look at an <code>int</code>'s the
- largest and smallest possible value.</para>
+ <m:mo>=</m:mo>
- <para>A <xref linkend="glo_Java"/> <code
- xlink:href="https://docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html">int</code>
- is internally being represented by 4 <link
- linkend="glo_byte">bytes</link>. <inlineequation>
- <m:math display="inline">
- <m:msub>
- <m:mi>00000000000000000000000000000101</m:mi>
+ <m:mi>65535</m:mi>
+ </m:mrow>
+ </m:math>
+ </inlineequation>. So <code>'ڜ'</code> fits well into this
+ range.</para>
+
+ <para>According to the <link
+ xlink:href="https://en.wikipedia.org/wiki/Emoticons_(Unicode_block)">Emoticons
+ table</link> the smiley's code point value is U+1F60E being
+ equivalent to 128526 decimal. This exceeds the limit of 65535
+ and thus prohibits the character literal in question.</para>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+ </section>
+
+ <section xml:id="sd1SectIntMinMax">
+ <title>An <code>int</code>'s minimum and maximum value</title>
+
+ <qandaset defaultlabel="qanda" xml:id="sw1QandaMaxMinInt">
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>In this exercise we look at an <code>int</code>'s the
+ largest and smallest possible value.</para>
+
+ <para>A <xref linkend="glo_Java"/> <code
+ xlink:href="https://docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html">int</code>
+ is internally being represented by 4 <link
+ linkend="glo_byte">bytes</link>. <inlineequation>
+ <m:math display="inline">
+ <m:msub>
+ <m:mi>00000000000000000000000000000101</m:mi>
- <m:mi>2</m:mi>
- </m:msub>
- </m:math>
- </inlineequation> for example represents the decimal value
- 5.</para>
-
- <para>In order to represent negative values as well <xref
- linkend="glo_Java"/> uses <link
- xlink:href="https://en.wikipedia.org/wiki/Two's_complement#firstHeading">Two's
- complement</link> representation. We provide some values:</para>
-
- <table border="1" xml:id="sw1Table4ByteIntegerRepresentation">
- <caption>4 Byte <link
+ <m:mi>2</m:mi>
+ </m:msub>
+ </m:math>
+ </inlineequation> for example represents the decimal value
+ 5.</para>
+
+ <para>In order to represent negative values as well <xref
+ linkend="glo_Java"/> uses <link
xlink:href="https://en.wikipedia.org/wiki/Two's_complement#firstHeading">Two's
- complement</link> representation of <code>int</code>
- values.</caption>
+ complement</link> representation. We provide some
+ values:</para>
- <tr>
- <th>Two complement representation</th>
+ <table border="1" xml:id="sw1Table4ByteIntegerRepresentation">
+ <caption>4 Byte <link
+ xlink:href="https://en.wikipedia.org/wiki/Two's_complement#firstHeading">Two's
+ complement</link> representation of <code>int</code>
+ values.</caption>
- <th>Decimal representation</th>
- </tr>
+ <tr>
+ <th>Two complement representation</th>
- <tr>
- <td><code>00000000000000000000000000000000</code></td>
+ <th>Decimal representation</th>
+ </tr>
- <td>0</td>
- </tr>
+ <tr>
+ <td><code>00000000000000000000000000000000</code></td>
- <tr>
- <td><code>01111111111111111111111111111111</code></td>
+ <td>0</td>
+ </tr>
- <td><inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:msup>
- <m:mi>2</m:mi>
+ <tr>
+ <td><code>01111111111111111111111111111111</code></td>
- <m:mrow>
- <m:mi>16</m:mi>
+ <td><inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:msup>
+ <m:mi>2</m:mi>
- <m:mo>-</m:mo>
+ <m:mrow>
+ <m:mi>16</m:mi>
- <m:mi>1</m:mi>
- </m:mrow>
- </m:msup>
+ <m:mo>-</m:mo>
- <m:mo>-</m:mo>
+ <m:mi>1</m:mi>
+ </m:mrow>
+ </m:msup>
- <m:mi>1</m:mi>
- </m:mrow>
- </m:math>
- </inlineequation> (Maximum)</td>
- </tr>
+ <m:mo>-</m:mo>
- <tr>
- <td><code>10000000000000000000000000000000</code></td>
-
- <td><inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:mo>-</m:mo>
+ <m:mi>1</m:mi>
+ </m:mrow>
+ </m:math>
+ </inlineequation> (Maximum)</td>
+ </tr>
- <m:msup>
- <m:mi>2</m:mi>
+ <tr>
+ <td><code>10000000000000000000000000000000</code></td>
- <m:mrow>
- <m:mi>16</m:mi>
+ <td><inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:mo>-</m:mo>
- <m:mo>-</m:mo>
+ <m:msup>
+ <m:mi>2</m:mi>
- <m:mi>1</m:mi>
- </m:mrow>
- </m:msup>
- </m:mrow>
- </m:math>
- </inlineequation> (Minimum)</td>
- </tr>
+ <m:mrow>
+ <m:mi>16</m:mi>
- <tr>
- <td><code>11111111111111111111111111111111</code></td>
+ <m:mo>-</m:mo>
- <td>-1</td>
- </tr>
- </table>
-
- <para>Use <link
- xlink:href="https://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-3.10.1"><code>int</code>
- literals</link> in <link
- xlink:href="https://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-BinaryNumeral">binary
- representation</link> like e.g. <code>0B1100</code> in section
- <quote
- xlink:href="https://proquest.safaribooksonline.com/9780992133047/toc6_html_2">Literals</quote>
- in order to write an <code>int</code>'s minimum and maximum
- possible value to standard output.</para>
+ <m:mi>1</m:mi>
+ </m:mrow>
+ </m:msup>
+ </m:mrow>
+ </m:math>
+ </inlineequation> (Minimum)</td>
+ </tr>
+
+ <tr>
+ <td><code>11111111111111111111111111111111</code></td>
+
+ <td>-1</td>
+ </tr>
+ </table>
+
+ <para>Use <link
+ xlink:href="https://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-3.10.1"><code>int</code>
+ literals</link> in <link
+ xlink:href="https://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-BinaryNumeral">binary
+ representation</link> like e.g. <code>0B1100</code> in section
+ <quote
+ xlink:href="https://proquest.safaribooksonline.com/9780992133047/toc6_html_2">Literals</quote>
+ in order to write an <code>int</code>'s minimum and maximum
+ possible value to standard output.</para>
- <programlisting language="java"> public static void main(String[] args) {
+ <programlisting language="java"> public static void main(String[] args) {
int minumum = ... , //TODO: provide values by
maximum = ...; // binary int literals
@@ -1862,16 +1878,16 @@ System.out.println("Character: " + arabicChar);</programlisting>
System.out.println("Minimum:" + minumum);
System.out.println("Maximum:" + maximum);
}</programlisting>
- </question>
+ </question>
- <answer>
- <para>We insert <link
- xlink:href="https://en.wikipedia.org/wiki/Two's_complement#firstHeading">Two's
- complement</link> representations of minimum and maximum int
- values according to <xref
- linkend="sw1Table4ByteIntegerRepresentation"/>.</para>
+ <answer>
+ <para>We insert <link
+ xlink:href="https://en.wikipedia.org/wiki/Two's_complement#firstHeading">Two's
+ complement</link> representations of minimum and maximum int
+ values according to <xref
+ linkend="sw1Table4ByteIntegerRepresentation"/>.</para>
- <programlisting language="java">public static void main(String[] args) {
+ <programlisting language="java">public static void main(String[] args) {
int minumum = 0B10000000_00000000_00000000_00000000,
maximum = 0B01111111_11111111_11111111_11111111;
@@ -1880,76 +1896,76 @@ System.out.println("Character: " + arabicChar);</programlisting>
System.out.println("Maximum int value:" + maximum);
}</programlisting>
- <para>BTW: The <xref linkend="glo_JDK"/> does provide maximum
- value, minimum value and related information for
- <code>char</code>, <code>byte</code>, <code>short</code> and
- <code>int</code> data types int its related <classname
- xlink:href="https://docs.oracle.com/javase/8/docs/api/java/lang/Character.html">Character</classname>,
- <classname
- xlink:href="https://docs.oracle.com/javase/8/docs/api/java/lang/Byte.html">Byte</classname>,
- <classname
- xlink:href="https://docs.oracle.com/javase/8/docs/api/java/lang/Short.html">Short</classname>
- and <classname
- xlink:href="https://docs.oracle.com/javase/8/docs/api/java/lang/Integer.html">Integer</classname>
- classes. You may want to execute:</para>
-
- <programlisting language="java"> System.out.println("int minimum:" + Integer.MIN_VALUE);
+ <para>BTW: The <xref linkend="glo_JDK"/> does provide maximum
+ value, minimum value and related information for
+ <code>char</code>, <code>byte</code>, <code>short</code> and
+ <code>int</code> data types int its related <classname
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/java/lang/Character.html">Character</classname>,
+ <classname
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/java/lang/Byte.html">Byte</classname>,
+ <classname
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/java/lang/Short.html">Short</classname>
+ and <classname
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/java/lang/Integer.html">Integer</classname>
+ classes. You may want to execute:</para>
+
+ <programlisting language="java"> System.out.println("int minimum:" + Integer.MIN_VALUE);
System.out.println("int minimum:" + Integer.MAX_VALUE);
System.out.println("int bytes:" + Integer.BYTES);
System.out.println("int size:" + Integer.SIZE);
</programlisting>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+ </section>
</section>
- </section>
- <section xml:id="sw1SectSimpleExpressions">
- <title>Simple expressions</title>
+ <section xml:id="sw1SectSimpleExpressions">
+ <title>Simple expressions</title>
- <section xml:id="sd1SectCircleArea">
- <title>Calculating a circle area</title>
+ <section xml:id="sd1SectCircleArea">
+ <title>Calculating a circle area</title>
- <qandaset defaultlabel="qanda" xml:id="sw1QandaCircleArea">
- <qandadiv>
- <qandaentry>
- <question>
- <para>The area <inlineequation>
- <m:math display="inline">
- <m:mi>a</m:mi>
- </m:math>
- </inlineequation> of a given circle having radius
- <inlineequation>
- <m:math display="inline">
- <m:mi>r</m:mi>
- </m:math>
- </inlineequation> is being obtained by <inlineequation>
- <m:math display="inline">
- <m:mrow>
+ <qandaset defaultlabel="qanda" xml:id="sw1QandaCircleArea">
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>The area <inlineequation>
+ <m:math display="inline">
<m:mi>a</m:mi>
+ </m:math>
+ </inlineequation> of a given circle having radius
+ <inlineequation>
+ <m:math display="inline">
+ <m:mi>r</m:mi>
+ </m:math>
+ </inlineequation> is being obtained by <inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:mi>a</m:mi>
- <m:mo>=</m:mo>
+ <m:mo>=</m:mo>
- <m:mrow>
- <m:mi>Ï€</m:mi>
+ <m:mrow>
+ <m:mi>Ï€</m:mi>
- <m:mo>×</m:mo>
+ <m:mo>×</m:mo>
- <m:msup>
- <m:mi>r</m:mi>
+ <m:msup>
+ <m:mi>r</m:mi>
- <m:mi>2</m:mi>
- </m:msup>
+ <m:mi>2</m:mi>
+ </m:msup>
+ </m:mrow>
</m:mrow>
- </m:mrow>
- </m:math>
- </inlineequation>. Complete the following code to calculate
- the result and write it to standard output using
- <code>System.out.println(...)</code>:</para>
+ </m:math>
+ </inlineequation>. Complete the following code to calculate
+ the result and write it to standard output using
+ <code>System.out.println(...)</code>:</para>
- <programlisting language="java">public static void main(String[] args) {
+ <programlisting language="java">public static void main(String[] args) {
double radius = 2.31; // A circle having a radius (given e.g. in mm).
double pi = 3.1415926; // Constant relating a circle's radius,
@@ -1958,20 +1974,20 @@ System.out.println("Character: " + arabicChar);</programlisting>
// TODO: Write the circle's area to standard output
}</programlisting>
- <tip>
- <para>You may want to read the <link
- xlink:href="https://proquest.safaribooksonline.com/9780992133047/toc1_html_4">overview
- section</link> on statements.</para>
- </tip>
- </question>
+ <tip>
+ <para>You may want to read the <link
+ xlink:href="https://proquest.safaribooksonline.com/9780992133047/toc1_html_4">overview
+ section</link> on statements.</para>
+ </tip>
+ </question>
- <answer>
- <glosslist>
- <glossentry>
- <glossterm>Using a mere expression</glossterm>
+ <answer>
+ <glosslist>
+ <glossentry>
+ <glossterm>Using a mere expression</glossterm>
- <glossdef>
- <programlisting language="java">public static void main(String[] args) {
+ <glossdef>
+ <programlisting language="java">public static void main(String[] args) {
double radius = 2.31; // A circle having a radius (given e.g. in mm).
double pi = 3.1415926; // Constant relating a circle's radius,
@@ -1979,19 +1995,19 @@ System.out.println("Character: " + arabicChar);</programlisting>
System.out.println(pi * radius * radius);
}</programlisting>
- </glossdef>
- </glossentry>
+ </glossdef>
+ </glossentry>
- <glossentry>
- <glossterm>Using a variable</glossterm>
+ <glossentry>
+ <glossterm>Using a variable</glossterm>
- <glossdef>
- <para>Instead of immediately using the expression as an
- argument to <code>System.out.println(...)</code> we may
- assign its value to a variable prior to output
- creation:</para>
+ <glossdef>
+ <para>Instead of immediately using the expression as an
+ argument to <code>System.out.println(...)</code> we may
+ assign its value to a variable prior to output
+ creation:</para>
- <programlisting language="java">public static void main(String[] args) {
+ <programlisting language="java">public static void main(String[] args) {
double radius = 2.31; // A circle having a radius (given e.g. in mm).
double pi = 3.1415926; // Constant relating a circle's radius,
@@ -2000,27 +2016,27 @@ System.out.println("Character: " + arabicChar);</programlisting>
double area = pi * radius * radius;
System.out.println(area);
}</programlisting>
- </glossdef>
- </glossentry>
- </glosslist>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
- </section>
-
- <section xml:id="sd1SectTemperatureConvert">
- <title>Converting temperature values</title>
-
- <qandaset defaultlabel="qanda" xml:id="sd1QandaTemperatureConvert">
- <qandadiv>
- <qandaentry>
- <question>
- <para>Write an application converting temperature values being
- represented as degree centigrade to kelvin and
- Fahrenheit:</para>
-
- <programlisting language="java"> public static void main(String[] args) {
+ </glossdef>
+ </glossentry>
+ </glosslist>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+ </section>
+
+ <section xml:id="sd1SectTemperatureConvert">
+ <title>Converting temperature values</title>
+
+ <qandaset defaultlabel="qanda" xml:id="sd1QandaTemperatureConvert">
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>Write an application converting temperature values being
+ represented as degree centigrade to kelvin and
+ Fahrenheit:</para>
+
+ <programlisting language="java"> public static void main(String[] args) {
double temperatureCelsius = 23.2;
@@ -2030,10 +2046,10 @@ System.out.println("Character: " + arabicChar);</programlisting>
System.out.println("Kelvin: " + temperatureKelvin);
System.out.println("Fahrenheit: " + temperatureFahrenheit);
}</programlisting>
- </question>
+ </question>
- <answer>
- <programlisting language="java"> public static void main(String[] args) {
+ <answer>
+ <programlisting language="java"> public static void main(String[] args) {
double temperatureCelsius = 23.2;
@@ -2045,27 +2061,27 @@ System.out.println("Character: " + arabicChar);</programlisting>
System.out.println("Kelvin: " + temperatureKelvin);
System.out.println("Fahrenheit: " + temperatureFahrenheit);
}</programlisting>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
- </section>
-
- <section xml:id="sd1SectTimeUnits">
- <title>Time unit conversion</title>
-
- <qandaset defaultlabel="qanda" xml:id="sd1QandaTimeUnits">
- <qandadiv>
- <qandaentry>
- <question>
- <para>This exercise consists of two parts:</para>
-
- <orderedlist>
- <listitem>
- <para>Write an application converting a (seconds, minutes
- ,hours) time specification to seconds:</para>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+ </section>
+
+ <section xml:id="sd1SectTimeUnits">
+ <title>Time unit conversion</title>
+
+ <qandaset defaultlabel="qanda" xml:id="sd1QandaTimeUnits">
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>This exercise consists of two parts:</para>
+
+ <orderedlist>
+ <listitem>
+ <para>Write an application converting a (seconds, minutes
+ ,hours) time specification to seconds:</para>
- <programlisting language="java"> public static void main(String[] args) {
+ <programlisting language="java"> public static void main(String[] args) {
final int
seconds = 31,
@@ -2077,17 +2093,17 @@ System.out.println("Character: " + arabicChar);</programlisting>
System.out.println("Time in seconds:" + timeInSeconds);
}</programlisting>
- <para>The expected output reads:</para>
+ <para>The expected output reads:</para>
- <programlisting language="none">Time in seconds:15391</programlisting>
- </listitem>
+ <programlisting language="none">Time in seconds:15391</programlisting>
+ </listitem>
- <listitem>
- <para>Reverse the previous part of this exercise: Convert a
- time specification in seconds to (seconds, minutes ,hours)
- as in:</para>
+ <listitem>
+ <para>Reverse the previous part of this exercise: Convert
+ a time specification in seconds to (seconds, minutes
+ ,hours) as in:</para>
- <programlisting language="java"> public static void main(String[] args) {
+ <programlisting language="java"> public static void main(String[] args) {
final int timeInSeconds = 15391;
@@ -2098,27 +2114,28 @@ System.out.println("Character: " + arabicChar);</programlisting>
System.out.println("Seconds:" + seconds);
}</programlisting>
- <para>The expected output reads:</para>
+ <para>The expected output reads:</para>
- <programlisting language="none">Hours:4
+ <programlisting language="none">Hours:4
Minutes:16
Seconds:31</programlisting>
- <tip>
- <para>Consider the <link
- xlink:href="https://docs.oracle.com/javase/tutorial/java/nutsandbolts/op1.html">remainder
- operator <quote>%</quote></link> (modulo operator).</para>
- </tip>
- </listitem>
- </orderedlist>
- </question>
+ <tip>
+ <para>Consider the <link
+ xlink:href="https://docs.oracle.com/javase/tutorial/java/nutsandbolts/op1.html">remainder
+ operator <quote>%</quote></link> (modulo
+ operator).</para>
+ </tip>
+ </listitem>
+ </orderedlist>
+ </question>
- <answer>
- <orderedlist>
- <listitem>
- <para>A straightforward solution reads:</para>
+ <answer>
+ <orderedlist>
+ <listitem>
+ <para>A straightforward solution reads:</para>
- <para><programlisting language="java"> public static void main(String[] args) {
+ <para><programlisting language="java"> public static void main(String[] args) {
final int
seconds = 31,
@@ -2129,10 +2146,10 @@ Seconds:31</programlisting>
System.out.println("Time in seconds:" + timeInSeconds);
}</programlisting></para>
- </listitem>
+ </listitem>
- <listitem>
- <programlisting language="java"> public static void main(String[] args) {
+ <listitem>
+ <programlisting language="java"> public static void main(String[] args) {
final int timeInSeconds = 15391;
@@ -2146,618 +2163,622 @@ Seconds:31</programlisting>
System.out.println("Minutes:" + minutes);
System.out.println("Seconds:" + seconds);
}</programlisting>
- </listitem>
- </orderedlist>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
- </section>
-
- <section xml:id="sd1_sect_typeAssignCompat">
- <title>Assignment and type safety</title>
-
- <qandaset defaultlabel="qanda" xml:id="sd1_qanda_typeAssignCompat">
- <qandadiv>
- <qandaentry>
- <question>
- <para>We consider:</para>
-
- <programlisting language="java">int i = -21;
+ </listitem>
+ </orderedlist>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+ </section>
+
+ <section xml:id="sd1_sect_typeAssignCompat">
+ <title>Assignment and type safety</title>
+
+ <qandaset defaultlabel="qanda" xml:id="sd1_qanda_typeAssignCompat">
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>We consider:</para>
+
+ <programlisting language="java">int i = -21;
double d = i;</programlisting>
- <para>This snippet shows perfectly correct <xref
- linkend="glo_Java"/> code. However <xref
- linkend="sd1_fig_typeSafety"/> suggests we should not be allowed
- to assign an <code>int</code> to a <code>double</code> value due
- to type safety.</para>
+ <para>This snippet shows perfectly correct <xref
+ linkend="glo_Java"/> code. However <xref
+ linkend="sd1_fig_typeSafety"/> suggests we should not be
+ allowed to assign an <code>int</code> to a <code>double</code>
+ value due to type safety.</para>
- <para>Even worse: Swapping types yields a compile time
- error:</para>
+ <para>Even worse: Swapping types yields a compile time
+ error:</para>
- <programlisting language="java">double d = 2.4;
+ <programlisting language="java">double d = 2.4;
int i = d; // Error: Incompatible types</programlisting>
- <para>Why is this? Make an educated guess.</para>
- </question>
-
- <answer>
- <para>The first snippet compiles by using the widening
- conversion: When assigning <code>d = i</code> the <xref
- linkend="glo_Java"/> compiler implicitly converts the
- <code>int</code> into a <code>double</code> value.</para>
-
- <para>Turning a double into an int is more cumbersome: The
- expression <code>i = 3.5</code> could be evaluated by agreeing
- on a specific rounding prescription. But what about i =
- 3457357385783573478955345.45? A <xref linkend="glo_Java"/>
- <code>int</code>'s maximum value is <inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:msup>
- <m:mi>2</m:mi>
+ <para>Why is this? Make an educated guess.</para>
+ </question>
+
+ <answer>
+ <para>The first snippet compiles by using the widening
+ conversion: When assigning <code>d = i</code> the <xref
+ linkend="glo_Java"/> compiler implicitly converts the
+ <code>int</code> into a <code>double</code> value.</para>
+
+ <para>Turning a double into an int is more cumbersome: The
+ expression <code>i = 3.5</code> could be evaluated by agreeing
+ on a specific rounding prescription. But what about i =
+ 3457357385783573478955345.45? A <xref linkend="glo_Java"/>
+ <code>int</code>'s maximum value is <inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:msup>
+ <m:mi>2</m:mi>
- <m:mi>31</m:mi>
- </m:msup>
+ <m:mi>31</m:mi>
+ </m:msup>
- <m:mo>-</m:mo>
+ <m:mo>-</m:mo>
- <m:mi>1</m:mi>
- </m:mrow>
- </m:math>
- </inlineequation>exceeding the former <code>double</code>
- value.</para>
+ <m:mi>1</m:mi>
+ </m:mrow>
+ </m:math>
+ </inlineequation>exceeding the former <code>double</code>
+ value.</para>
- <para>Conclusion: <xref linkend="glo_Java"/> disallows double to
- int assignments unless using a so called cast (explicit type
- conversion):</para>
+ <para>Conclusion: <xref linkend="glo_Java"/> disallows double
+ to int assignments unless using a so called cast (explicit
+ type conversion):</para>
- <programlisting language="java">double d = 2.4;
+ <programlisting language="java">double d = 2.4;
int i = (int) d; // Explicit cast double to int</programlisting>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
- </section>
-
- <section xml:id="sd1SectLong2Float">
- <title>Reducing <code>long</code> to <code>int</code></title>
-
- <qandaset defaultlabel="qanda" xml:id="sd1QandaLong2Float">
- <qandadiv>
- <qandaentry>
- <question>
- <para>Joe programmer intends to map positive <code>long</code>
- values to <code>int</code> values. This requires scaling down
- <quote>half</quote> the <code>long</code> data type's range
- <inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:mo>[</m:mo>
-
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+ </section>
+
+ <section xml:id="sd1SectLong2Float">
+ <title>Reducing <code>long</code> to <code>int</code></title>
+
+ <qandaset defaultlabel="qanda" xml:id="sd1QandaLong2Float">
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>Joe programmer intends to map positive <code>long</code>
+ values to <code>int</code> values. This requires scaling down
+ <quote>half</quote> the <code>long</code> data type's range
+ <inlineequation>
+ <m:math display="inline">
<m:mrow>
- <m:mn>0</m:mn>
-
- <m:mo>,</m:mo>
+ <m:mo>[</m:mo>
<m:mrow>
- <m:msup>
- <m:mi>2</m:mi>
+ <m:mn>0</m:mn>
- <m:mi>63</m:mi>
- </m:msup>
+ <m:mo>,</m:mo>
- <m:mo>-</m:mo>
+ <m:mrow>
+ <m:msup>
+ <m:mi>2</m:mi>
- <m:mi>1</m:mi>
- </m:mrow>
- </m:mrow>
+ <m:mi>63</m:mi>
+ </m:msup>
- <m:mo>]</m:mo>
- </m:mrow>
- </m:math>
- </inlineequation> to the <code>int</code>'s range of
- <inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:mo>[</m:mo>
+ <m:mo>-</m:mo>
- <m:mrow>
- <m:mn>0</m:mn>
+ <m:mi>1</m:mi>
+ </m:mrow>
+ </m:mrow>
- <m:mo>,</m:mo>
+ <m:mo>]</m:mo>
+ </m:mrow>
+ </m:math>
+ </inlineequation> to the <code>int</code>'s range of
+ <inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:mo>[</m:mo>
<m:mrow>
- <m:msup>
- <m:mi>2</m:mi>
-
- <m:mi>31</m:mi>
- </m:msup>
-
- <m:mo>-</m:mo>
+ <m:mn>0</m:mn>
- <m:mi>1</m:mi>
- </m:mrow>
- </m:mrow>
+ <m:mo>,</m:mo>
- <m:mo>]</m:mo>
- </m:mrow>
- </m:math>
- </inlineequation>:</para>
+ <m:mrow>
+ <m:msup>
+ <m:mi>2</m:mi>
- <informaltable border="1">
- <colgroup width="25%"/>
+ <m:mi>31</m:mi>
+ </m:msup>
- <colgroup width="30%"/>
+ <m:mo>-</m:mo>
- <colgroup width="15%"/>
-
- <colgroup width="30%"/>
+ <m:mi>1</m:mi>
+ </m:mrow>
+ </m:mrow>
- <tr>
- <th colspan="2">From</th>
+ <m:mo>]</m:mo>
+ </m:mrow>
+ </m:math>
+ </inlineequation>:</para>
- <th colspan="2">To</th>
- </tr>
+ <informaltable border="1">
+ <colgroup width="25%"/>
- <tr>
- <th><code>long</code></th>
+ <colgroup width="30%"/>
- <th><code>remark</code></th>
+ <colgroup width="15%"/>
- <th><code>int</code></th>
+ <colgroup width="30%"/>
- <th>remark</th>
- </tr>
+ <tr>
+ <th colspan="2">From</th>
- <tr>
- <td align="right">0</td>
+ <th colspan="2">To</th>
+ </tr>
- <td align="right"/>
+ <tr>
+ <th><code>long</code></th>
- <td align="right">0</td>
+ <th><code>remark</code></th>
- <td align="right"/>
- </tr>
+ <th><code>int</code></th>
- <tr>
- <td align="right">1</td>
+ <th>remark</th>
+ </tr>
- <td align="right"/>
+ <tr>
+ <td align="right">0</td>
- <td align="right">0</td>
+ <td align="right"/>
- <td align="right"/>
- </tr>
+ <td align="right">0</td>
- <tr>
- <td align="center" colspan="2">...</td>
+ <td align="right"/>
+ </tr>
- <td align="right">0</td>
+ <tr>
+ <td align="right">1</td>
- <td align="center">...</td>
- </tr>
+ <td align="right"/>
- <tr>
- <td align="right">4294967295</td>
+ <td align="right">0</td>
- <td align="right"><inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:msup>
- <m:mi>2</m:mi>
+ <td align="right"/>
+ </tr>
- <m:mi>32</m:mi>
- </m:msup>
+ <tr>
+ <td align="center" colspan="2">...</td>
- <m:mo>-</m:mo>
+ <td align="right">0</td>
- <m:mi>1</m:mi>
- </m:mrow>
- </m:math>
- </inlineequation></td>
+ <td align="center">...</td>
+ </tr>
- <td align="right">0</td>
+ <tr>
+ <td align="right">4294967295</td>
- <td align="right"/>
- </tr>
+ <td align="right"><inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:msup>
+ <m:mi>2</m:mi>
- <tr>
- <td align="right">4294967296</td>
+ <m:mi>32</m:mi>
+ </m:msup>
- <td align="right"><inlineequation>
- <m:math display="inline">
- <m:msup>
- <m:mi>2</m:mi>
+ <m:mo>-</m:mo>
- <m:mi>32</m:mi>
- </m:msup>
- </m:math>
- </inlineequation></td>
+ <m:mi>1</m:mi>
+ </m:mrow>
+ </m:math>
+ </inlineequation></td>
- <td align="right">1</td>
+ <td align="right">0</td>
- <td align="right"/>
- </tr>
+ <td align="right"/>
+ </tr>
- <tr>
- <td align="right">4294967297</td>
+ <tr>
+ <td align="right">4294967296</td>
- <td align="right"><inlineequation>
- <m:math display="inline">
- <m:mrow>
+ <td align="right"><inlineequation>
+ <m:math display="inline">
<m:msup>
<m:mi>2</m:mi>
<m:mi>32</m:mi>
</m:msup>
+ </m:math>
+ </inlineequation></td>
- <m:mo>+</m:mo>
+ <td align="right">1</td>
- <m:mi>1</m:mi>
- </m:mrow>
- </m:math>
- </inlineequation></td>
+ <td align="right"/>
+ </tr>
- <td align="right">1</td>
+ <tr>
+ <td align="right">4294967297</td>
- <td align="right"/>
- </tr>
+ <td align="right"><inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:msup>
+ <m:mi>2</m:mi>
- <tr>
- <td align="center" colspan="4">...</td>
- </tr>
+ <m:mi>32</m:mi>
+ </m:msup>
- <tr>
- <td align="right">9223372036854775806</td>
+ <m:mo>+</m:mo>
- <td align="right"><inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:msup>
- <m:mi>2</m:mi>
+ <m:mi>1</m:mi>
+ </m:mrow>
+ </m:math>
+ </inlineequation></td>
- <m:mi>63</m:mi>
- </m:msup>
+ <td align="right">1</td>
- <m:mo>-</m:mo>
+ <td align="right"/>
+ </tr>
- <m:mi>2</m:mi>
- </m:mrow>
- </m:math>
- </inlineequation> or <code
- xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Long.MAX_VALUE"><varname
- xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Long.MAX_VALUE">Long.MAX_VALUE</varname></code>
- - 1</td>
+ <tr>
+ <td align="center" colspan="4">...</td>
+ </tr>
- <td align="right">2147483647</td>
+ <tr>
+ <td align="right">9223372036854775806</td>
- <td align="right"><inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:msup>
- <m:mi>2</m:mi>
+ <td align="right"><inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:msup>
+ <m:mi>2</m:mi>
- <m:mi>31</m:mi>
- </m:msup>
+ <m:mi>63</m:mi>
+ </m:msup>
- <m:mo>-</m:mo>
+ <m:mo>-</m:mo>
- <m:mi>1</m:mi>
- </m:mrow>
- </m:math>
- </inlineequation> or <varname
- xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Integer.MAX_VALUE">Integer.MAX_VALUE</varname></td>
- </tr>
+ <m:mi>2</m:mi>
+ </m:mrow>
+ </m:math>
+ </inlineequation> or <code
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Long.MAX_VALUE"><varname
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Long.MAX_VALUE">Long.MAX_VALUE</varname></code>
+ - 1</td>
- <tr>
- <td align="right">9223372036854775807</td>
+ <td align="right">2147483647</td>
- <td align="right"><inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:msup>
- <m:mi>2</m:mi>
+ <td align="right"><inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:msup>
+ <m:mi>2</m:mi>
- <m:mi>63</m:mi>
- </m:msup>
+ <m:mi>31</m:mi>
+ </m:msup>
- <m:mo>-</m:mo>
+ <m:mo>-</m:mo>
- <m:mi>1</m:mi>
- </m:mrow>
- </m:math>
- </inlineequation> or <varname
- xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Long.MAX_VALUE">Long.MAX_VALUE</varname></td>
+ <m:mi>1</m:mi>
+ </m:mrow>
+ </m:math>
+ </inlineequation> or <varname
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Integer.MAX_VALUE">Integer.MAX_VALUE</varname></td>
+ </tr>
- <td align="right">2147483647</td>
+ <tr>
+ <td align="right">9223372036854775807</td>
- <td align="right"><inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:msup>
- <m:mi>2</m:mi>
+ <td align="right"><inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:msup>
+ <m:mi>2</m:mi>
- <m:mi>31</m:mi>
- </m:msup>
+ <m:mi>63</m:mi>
+ </m:msup>
- <m:mo>-</m:mo>
+ <m:mo>-</m:mo>
- <m:mi>1</m:mi>
- </m:mrow>
- </m:math>
- </inlineequation> or <varname
- xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Integer.MAX_VALUE">Integer.MAX_VALUE</varname></td>
- </tr>
- </informaltable>
+ <m:mi>1</m:mi>
+ </m:mrow>
+ </m:math>
+ </inlineequation> or <varname
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Long.MAX_VALUE">Long.MAX_VALUE</varname></td>
- <para>Joe's idea is dividing <code>long</code> values by
- <inlineequation>
- <m:math display="inline">
- <m:msup>
- <m:mi>2</m:mi>
+ <td align="right">2147483647</td>
- <m:mi>32</m:mi>
- </m:msup>
- </m:math>
- </inlineequation>. As a result a long value of <inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:mo>-</m:mo>
+ <td align="right"><inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:msup>
+ <m:mi>2</m:mi>
+
+ <m:mi>31</m:mi>
+ </m:msup>
+
+ <m:mo>-</m:mo>
+ <m:mi>1</m:mi>
+ </m:mrow>
+ </m:math>
+ </inlineequation> or <varname
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Integer.MAX_VALUE">Integer.MAX_VALUE</varname></td>
+ </tr>
+ </informaltable>
+
+ <para>Joe's idea is dividing <code>long</code> values by
+ <inlineequation>
+ <m:math display="inline">
<m:msup>
<m:mi>2</m:mi>
- <m:mi>63</m:mi>
+ <m:mi>32</m:mi>
</m:msup>
- </m:mrow>
- </m:math>
- </inlineequation> will be reduced to the intended value of
- <inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:mo>-</m:mo>
+ </m:math>
+ </inlineequation>. As a result a long value of
+ <inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:mo>-</m:mo>
+
+ <m:msup>
+ <m:mi>2</m:mi>
+
+ <m:mi>63</m:mi>
+ </m:msup>
+ </m:mrow>
+ </m:math>
+ </inlineequation> will be reduced to the intended value of
+ <inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:mo>-</m:mo>
+
+ <m:msup>
+ <m:mi>2</m:mi>
+ <m:mi>31</m:mi>
+ </m:msup>
+ </m:mrow>
+ </m:math>
+ </inlineequation>. Since <inlineequation>
+ <m:math display="inline">
<m:msup>
<m:mi>2</m:mi>
- <m:mi>31</m:mi>
+ <m:mi>32</m:mi>
</m:msup>
- </m:mrow>
- </m:math>
- </inlineequation>. Since <inlineequation>
- <m:math display="inline">
- <m:msup>
- <m:mi>2</m:mi>
-
- <m:mi>32</m:mi>
- </m:msup>
- </m:math>
- </inlineequation> seems to be equal to <code>2 * (<link
- xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Integer.MAX_VALUE">Integer.MAX_VALUE</link>
- + 1))</code> (why?) Joe's first attempt reads:</para>
+ </m:math>
+ </inlineequation> seems to be equal to <code>2 * (<link
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/constant-values.html#java.lang.Integer.MAX_VALUE">Integer.MAX_VALUE</link>
+ + 1))</code> (why?) Joe's first attempt reads:</para>
- <programlisting language="java" linenumbering="numbered"
- startinglinenumber="26">final long longValue = 2147483648L;
+ <programlisting language="java" linenumbering="numbered"
+ startinglinenumber="26">final long longValue = 2147483648L;
final int reducedValue = (int) (longValue / (2 * (Integer.MAX_VALUE + 1)));
System.out.println(reducedValue);</programlisting>
- <para>Unfortunately the results are not promising. This code
- merely results in a runtime error:</para>
+ <para>Unfortunately the results are not promising. This code
+ merely results in a runtime error:</para>
- <programlisting language="none">/usr/lib/jvm/java-8-oracle/bin/java ...
+ <programlisting language="none">/usr/lib/jvm/java-8-oracle/bin/java ...
Exception in thread "main" java.lang.ArithmeticException: / by zero
at qq.App.main(App.java:27)
Process finished with exit code 1</programlisting>
- <para>Explain the underlying problem and correct Joe's
- error.</para>
+ <para>Explain the underlying problem and correct Joe's
+ error.</para>
- <tip>
- <para>It may be helpful thinking of a smaller example before.
- Consider hypothetic integer types <quote>TinyLong</quote> and
- <quote>TinyInt</quote> requiring 4 and 2 bits
- respectively.</para>
- </tip>
- </question>
+ <tip>
+ <para>It may be helpful thinking of a smaller example
+ before. Consider hypothetic integer types
+ <quote>TinyLong</quote> and <quote>TinyInt</quote> requiring
+ 4 and 2 bits respectively.</para>
+ </tip>
+ </question>
- <answer>
- <para>As a prerequisite we represent the scaling of a hypothetic
- integer type <quote>TinyLong</quote> to a smaller type
- <quote>TinyInt</quote> of 4 and 2 bits respectively:</para>
+ <answer>
+ <para>As a prerequisite we represent the scaling of a
+ hypothetic integer type <quote>TinyLong</quote> to a smaller
+ type <quote>TinyInt</quote> of 4 and 2 bits
+ respectively:</para>
- <informaltable border="1">
- <colgroup width="20%"/>
+ <informaltable border="1">
+ <colgroup width="20%"/>
- <colgroup width="5%"/>
+ <colgroup width="5%"/>
- <colgroup width="5%"/>
+ <colgroup width="5%"/>
- <colgroup width="5%"/>
+ <colgroup width="5%"/>
- <colgroup width="5%"/>
+ <colgroup width="5%"/>
- <colgroup width="5%"/>
+ <colgroup width="5%"/>
- <colgroup width="5%"/>
+ <colgroup width="5%"/>
- <colgroup width="5%"/>
+ <colgroup width="5%"/>
- <colgroup width="5%"/>
+ <colgroup width="5%"/>
- <colgroup width="5%"/>
+ <colgroup width="5%"/>
- <colgroup width="5%"/>
+ <colgroup width="5%"/>
- <colgroup width="5%"/>
+ <colgroup width="5%"/>
- <colgroup width="5%"/>
+ <colgroup width="5%"/>
- <colgroup width="5%"/>
+ <colgroup width="5%"/>
- <colgroup width="5%"/>
+ <colgroup width="5%"/>
- <colgroup width="5%"/>
+ <colgroup width="5%"/>
- <colgroup width="5%"/>
+ <colgroup width="5%"/>
- <tr>
- <td><quote>TinyLong</quote>, n = 4</td>
+ <tr>
+ <td><quote>TinyLong</quote>, n = 4</td>
- <td>-8</td>
+ <td>-8</td>
- <td>-7</td>
+ <td>-7</td>
- <td>-6</td>
+ <td>-6</td>
- <td>-5</td>
+ <td>-5</td>
- <td>-4</td>
+ <td>-4</td>
- <td>-3</td>
+ <td>-3</td>
- <td>-2</td>
+ <td>-2</td>
- <td>-1</td>
+ <td>-1</td>
- <td>0</td>
+ <td>0</td>
- <td>1</td>
+ <td>1</td>
- <td>2</td>
+ <td>2</td>
- <td>3</td>
+ <td>3</td>
- <td>4</td>
+ <td>4</td>
- <td>5</td>
+ <td>5</td>
- <td>6</td>
+ <td>6</td>
- <td>7</td>
- </tr>
+ <td>7</td>
+ </tr>
- <tr>
- <td><quote>TinyInt</quote>, n = 2</td>
+ <tr>
+ <td><quote>TinyInt</quote>, n = 2</td>
- <td colspan="4">-2</td>
+ <td colspan="4">-2</td>
- <td colspan="4">-1</td>
+ <td colspan="4">-1</td>
- <td colspan="4">0</td>
+ <td colspan="4">0</td>
- <td colspan="4">1</td>
- </tr>
- </informaltable>
+ <td colspan="4">1</td>
+ </tr>
+ </informaltable>
- <para>Joe's assumption for these particular values implies
- dividing <quote>TinyLong</quote> values by <inlineequation>
- <m:math display="inline">
- <m:msup>
- <m:mi>2</m:mi>
+ <para>Joe's assumption for these particular values implies
+ dividing <quote>TinyLong</quote> values by <inlineequation>
+ <m:math display="inline">
+ <m:msup>
+ <m:mi>2</m:mi>
- <m:mi>2</m:mi>
- </m:msup>
- </m:math>
- </inlineequation> (truncating). This indeed yields the desired
- result for non-negative values. So why does Joe encounter a
- division by zero runtime exception when executing
- <code>longValue / (2 * (Integer.MAX_VALUE + 1))</code> ?</para>
+ <m:mi>2</m:mi>
+ </m:msup>
+ </m:math>
+ </inlineequation> (truncating). This indeed yields the
+ desired result for non-negative values. So why does Joe
+ encounter a division by zero runtime exception when executing
+ <code>longValue / (2 * (Integer.MAX_VALUE + 1))</code>
+ ?</para>
- <para>Unfortunately Joe's implementation is seriously flawed for
- even two reasons:</para>
+ <para>Unfortunately Joe's implementation is seriously flawed
+ for even two reasons:</para>
- <orderedlist>
- <listitem>
- <para>The constant <code>Integer.MAX_VALUE</code> already
- suggests we will not be able to increase its value while
- staying as an <code>int</code>. The expression
- <code>Integer.MAX_VALUE + 1</code> will be evaluated using
- <code>int</code> rather than <code>long</code> arithmetic
- thus returning <code>Integer.MIN_VALUE</code> (negative!)
- due to an arithmetic overflow:</para>
-
- <programlisting language="java"> 01111111_11111111_11111111_11111111
+ <orderedlist>
+ <listitem>
+ <para>The constant <code>Integer.MAX_VALUE</code> already
+ suggests we will not be able to increase its value while
+ staying as an <code>int</code>. The expression
+ <code>Integer.MAX_VALUE + 1</code> will be evaluated using
+ <code>int</code> rather than <code>long</code> arithmetic
+ thus returning <code>Integer.MIN_VALUE</code> (negative!)
+ due to an arithmetic overflow:</para>
+
+ <programlisting language="java"> 01111111_11111111_11111111_11111111
+ 00000000_00000000_00000000_00000001
_____________________________________
10000000_00000000_00000000_00000000</programlisting>
- <para>The expression <code>2 * (Integer.MAX_VALUE +
- 1)</code> then gives rise to a second overflow error:</para>
+ <para>The expression <code>2 * (Integer.MAX_VALUE +
+ 1)</code> then gives rise to a second overflow
+ error:</para>
- <programlisting language="java"> 10000000_00000000_00000000_00000000
+ <programlisting language="java"> 10000000_00000000_00000000_00000000
+ 10000000_00000000_00000000_00000000
_____________________________________
00000000_00000000_00000000_00000000</programlisting>
- </listitem>
- </orderedlist>
-
- <para>Both errors combined (surprisingly) result in a value of
- <code>0</code> explaining the <quote>division by zero</quote>
- error message. There are two possible solutions:</para>
-
- <glosslist>
- <glossentry>
- <glossterm><code>(int) (longValue / (2L * (Integer.MAX_VALUE
- + 1L)))</code></glossterm>
-
- <glossdef>
- <para>Introducing <code>2L</code> or <code>1L</code> (one
- is sufficient) in favour of simply using 2 and 1 turns
- both addition and multiplication into operations involving
- at least one long argument. Thus for both operations the
- <xref linkend="glo_Java"/> runtime will use
- <code>long</code> arithmetic returning the desired
- <quote>reducing</quote> factor of <inlineequation>
- <m:math display="inline">
- <m:msup>
- <m:mi>2</m:mi>
-
- <m:mi>32</m:mi>
- </m:msup>
- </m:math>
- </inlineequation> of type <code>long</code>.</para>
- </glossdef>
- </glossentry>
-
- <glossentry>
- <glossterm><code>(int) (longValue / 2 / (Integer.MAX_VALUE +
- 1L))</code></glossterm>
-
- <glossdef>
- <para>Same result as before.</para>
-
- <note>
- <para>This time the expression starts with
- <code>longValue / 2 ...</code> Since the variable
- <code>longValue</code> is of type <code>long</code> the
- expression <code>longValue / 2</code> will be evaluated
- by the <xref linkend="glo_Java"/> runtime using
- <code>long</code> arithmetics. The result will
- subsequently be multiplied with <code>Integer.MAX_VALUE
- + 1L</code> again using <code>long</code>
- arithmetic.</para>
- </note>
- </glossdef>
- </glossentry>
- </glosslist>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
- </section>
-
- <section xml:id="sd1SectFloatPrecisionProblem">
- <title>Representational float and double miracles</title>
-
- <qandaset defaultlabel="qanda" xml:id="sd1QandaFloatPrecisionProblem">
- <qandadiv>
- <qandaentry>
- <question>
- <para>Consider and execute the following code snippet:</para>
-
- <programlisting language="java">public static void main(String[] args) {
+ </listitem>
+ </orderedlist>
+
+ <para>Both errors combined (surprisingly) result in a value of
+ <code>0</code> explaining the <quote>division by zero</quote>
+ error message. There are two possible solutions:</para>
+
+ <glosslist>
+ <glossentry>
+ <glossterm><code>(int) (longValue / (2L *
+ (Integer.MAX_VALUE + 1L)))</code></glossterm>
+
+ <glossdef>
+ <para>Introducing <code>2L</code> or <code>1L</code>
+ (one is sufficient) in favour of simply using 2 and 1
+ turns both addition and multiplication into operations
+ involving at least one long argument. Thus for both
+ operations the <xref linkend="glo_Java"/> runtime will
+ use <code>long</code> arithmetic returning the desired
+ <quote>reducing</quote> factor of <inlineequation>
+ <m:math display="inline">
+ <m:msup>
+ <m:mi>2</m:mi>
+
+ <m:mi>32</m:mi>
+ </m:msup>
+ </m:math>
+ </inlineequation> of type <code>long</code>.</para>
+ </glossdef>
+ </glossentry>
+
+ <glossentry>
+ <glossterm><code>(int) (longValue / 2 / (Integer.MAX_VALUE
+ + 1L))</code></glossterm>
+
+ <glossdef>
+ <para>Same result as before.</para>
+
+ <note>
+ <para>This time the expression starts with
+ <code>longValue / 2 ...</code> Since the variable
+ <code>longValue</code> is of type <code>long</code>
+ the expression <code>longValue / 2</code> will be
+ evaluated by the <xref linkend="glo_Java"/> runtime
+ using <code>long</code> arithmetics. The result will
+ subsequently be multiplied with
+ <code>Integer.MAX_VALUE + 1L</code> again using
+ <code>long</code> arithmetic.</para>
+ </note>
+ </glossdef>
+ </glossentry>
+ </glosslist>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+ </section>
+
+ <section xml:id="sd1SectFloatPrecisionProblem">
+ <title>Representational float and double miracles</title>
+
+ <qandaset defaultlabel="qanda" xml:id="sd1QandaFloatPrecisionProblem">
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>Consider and execute the following code snippet:</para>
+
+ <programlisting language="java">public static void main(String[] args) {
final double a = 0.7;
final double b = 0.9;
final double x = a + 0.1;
@@ -2765,80 +2786,82 @@ _____________________________________
System.out.println(x == y);
}</programlisting>
- <para>Explain the result and supply a possible solution.</para>
- </question>
+ <para>Explain the result and supply a possible
+ solution.</para>
+ </question>
- <answer>
- <para>The expression <code>x == y</code> evaluates to
- <code>false</code>. This surprising result is due to limited
- precision regarding both <code>float</code> and
- <code>double</code> IEEE representations: A given value will be
- approximated as close as possible.</para>
+ <answer>
+ <para>The expression <code>x == y</code> evaluates to
+ <code>false</code>. This surprising result is due to limited
+ precision regarding both <code>float</code> and
+ <code>double</code> IEEE representations: A given value will
+ be approximated as close as possible.</para>
- <para>Adding <code>System.out.println(x - y)</code> yields a
- value of -1.1102230246251565E-16 denoting the representational
- deviation of <code>x</code> and <code>y</code>.</para>
+ <para>Adding <code>System.out.println(x - y)</code> yields a
+ value of -1.1102230246251565E-16 denoting the representational
+ deviation of <code>x</code> and <code>y</code>.</para>
- <para>So we may compare <code>float</code> and
- <code>double</code> values by providing a representational error
- limit:</para>
+ <para>So we may compare <code>float</code> and
+ <code>double</code> values by providing a representational
+ error limit:</para>
- <programlisting language="java">final double a = 0.7;
+ <programlisting language="java">final double a = 0.7;
final double b = 0.9;
final double x = a + 0.1;
final double y = b - 0.1;
System.out.println(<link
- xlink:href="https://docs.oracle.com/javase/8/docs/api/java/lang/Math.html#abs-double-">Math.abs</link>(x - y) < 1.E-14);</programlisting>
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/java/lang/Math.html#abs-double-">Math.abs</link>(x - y) < 1.E-14);</programlisting>
- <para>This implements the boolean expression <inlineequation>
- <m:math display="inline">
- <m:mrow>
+ <para>This implements the boolean expression <inlineequation>
+ <m:math display="inline">
<m:mrow>
- <m:mo>|</m:mo>
-
<m:mrow>
- <m:mi>x</m:mi>
-
- <m:mo>-</m:mo>
-
- <m:mi>y</m:mi>
- </m:mrow>
+ <m:mo>|</m:mo>
- <m:mo>|</m:mo>
- </m:mrow>
-
- <m:mo><</m:mo>
+ <m:mrow>
+ <m:mi>x</m:mi>
- <m:msup>
- <m:mi>10</m:mi>
+ <m:mo>-</m:mo>
- <m:mrow>
- <m:mo>-</m:mo>
+ <m:mi>y</m:mi>
+ </m:mrow>
- <m:mi>14</m:mi>
+ <m:mo>|</m:mo>
</m:mrow>
- </m:msup>
- </m:mrow>
- </m:math>
- </inlineequation>.</para>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
- </section>
- <section xml:id="sd1SectInterestSimple">
- <title>Interest calculation</title>
+ <m:mo><</m:mo>
- <qandaset defaultlabel="qanda" xml:id="sd1QandaInterestSimple">
- <qandadiv>
- <qandaentry>
- <question>
- <para>We want to calculate the compounded interest starting from
- an initial capital, a given annual interest rate and a duration
- of three years. Consider the following code fragment:</para>
+ <m:msup>
+ <m:mi>10</m:mi>
+
+ <m:mrow>
+ <m:mo>-</m:mo>
- <programlisting language="java"> public static void main(String[] args) {
+ <m:mi>14</m:mi>
+ </m:mrow>
+ </m:msup>
+ </m:mrow>
+ </m:math>
+ </inlineequation>.</para>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+ </section>
+
+ <section xml:id="sd1SectInterestSimple">
+ <title>Interest calculation</title>
+
+ <qandaset defaultlabel="qanda" xml:id="sd1QandaInterestSimple">
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>We want to calculate the compounded interest starting
+ from an initial capital, a given annual interest rate and a
+ duration of three years. Consider the following code
+ fragment:</para>
+
+ <programlisting language="java"> public static void main(String[] args) {
final double initialCapital = 223.12;
final double interestRate = 1.5;
@@ -2851,43 +2874,43 @@ System.out.println(<link
System.out.println("Capital after three years:" + ...);
}</programlisting>
- <para>The expected output is:</para>
+ <para>The expected output is:</para>
- <programlisting language="none">Initial capital:223.12
+ <programlisting language="none">Initial capital:223.12
Annual interest rate:1.5
Capital after three years:233.31175902999993</programlisting>
- <tip>
- <para>In case you are unsure read about calculating the
- compounded interest.</para>
- </tip>
- </question>
+ <tip>
+ <para>In case you are unsure read about calculating the
+ compounded interest.</para>
+ </tip>
+ </question>
- <answer>
- <para>We obtain the compounded interest by multiplying the
- initial capital by <inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:mn>1</m:mn>
+ <answer>
+ <para>We obtain the compounded interest by multiplying the
+ initial capital by <inlineequation>
+ <m:math display="inline">
+ <m:mrow>
+ <m:mn>1</m:mn>
- <m:mo>+</m:mo>
+ <m:mo>+</m:mo>
- <m:mrow>
- <m:mi>r</m:mi>
+ <m:mrow>
+ <m:mi>r</m:mi>
- <m:mo>/</m:mo>
+ <m:mo>/</m:mo>
- <m:mn>100</m:mn>
+ <m:mn>100</m:mn>
+ </m:mrow>
</m:mrow>
- </m:mrow>
- </m:math>
- </inlineequation> for each year where r represents the given
- interest rate.</para>
+ </m:math>
+ </inlineequation> for each year where r represents the given
+ interest rate.</para>
- <para>Since we have not yet introduced loops this multiplication
- has to be repeated three times:</para>
+ <para>Since we have not yet introduced loops this
+ multiplication has to be repeated three times:</para>
- <programlisting language="java"> public static void main(String[] args) {
+ <programlisting language="java"> public static void main(String[] args) {
final double initialCapital = 223.12;
final double interestRate = 1.5;
@@ -2905,10 +2928,10 @@ Capital after three years:233.31175902999993</programlisting>
System.out.println("Capital after three years:" + capitalAtThreeYears);
}</programlisting>
- <para>We might as well use a single arithmetic expression to
- achieve the same result:</para>
+ <para>We might as well use a single arithmetic expression to
+ achieve the same result:</para>
- <programlisting language="java"> public static void main(String[] args) {
+ <programlisting language="java"> public static void main(String[] args) {
final double initialCapital = 223.12;
final double interestRate = 1.5;
@@ -2923,133 +2946,133 @@ Capital after three years:233.31175902999993</programlisting>
System.out.println("Capital after three years:" + capitalAtThreeYears);
}</programlisting>
- <para>In <xref linkend="sd1InterestCalculator"/> we will present
- a more elaborate solution based on loops and class
- methods.</para>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
- </section>
+ <para>In <xref linkend="sd1InterestCalculator"/> we will
+ present a more elaborate solution based on loops and class
+ methods.</para>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+ </section>
- <section xml:id="sd1ExpressionStrangeThings">
- <title>Strange things happen</title>
+ <section xml:id="sd1ExpressionStrangeThings">
+ <title>Strange things happen</title>
- <qandaset defaultlabel="qanda" xml:id="sw1QandaByteOverflow">
- <title>Byte integer arithmetics</title>
+ <qandaset defaultlabel="qanda" xml:id="sw1QandaByteOverflow">
+ <title>Byte integer arithmetics</title>
- <qandadiv>
- <qandaentry>
- <question>
- <para>Consider the following code snippet:</para>
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>Consider the following code snippet:</para>
- <programlisting language="java">byte a = 127;
+ <programlisting language="java">byte a = 127;
System.out.println("value=" + a);
a++;
System.out.println("New value=" + a);
</programlisting>
- <para>This will produce the following output:</para>
+ <para>This will produce the following output:</para>
- <programlisting language="none">value=127
+ <programlisting language="none">value=127
New value=-128</programlisting>
- <para>Explain this strange behaviour.</para>
+ <para>Explain this strange behaviour.</para>
- <para>Moreover you'll find the following code snippet yields a
- compile time error:</para>
+ <para>Moreover you'll find the following code snippet yields a
+ compile time error:</para>
- <programlisting language="java">byte a = 127;
+ <programlisting language="java">byte a = 127;
System.out.println("value=" + a);
a = a + 1; // Error: Type mismatch: cannot convert from int to byte
System.out.println("New value=" + a);</programlisting>
- <para>Explain this error's cause.</para>
+ <para>Explain this error's cause.</para>
- <tip>
- <para>You may want to read the <link
- xlink:href="https://proquest.safaribooksonline.com/9780992133047/toc1_html_4">overview
- section</link> on statements.</para>
- </tip>
- </question>
+ <tip>
+ <para>You may want to read the <link
+ xlink:href="https://proquest.safaribooksonline.com/9780992133047/toc1_html_4">overview
+ section</link> on statements.</para>
+ </tip>
+ </question>
- <answer>
- <para>A byte variable ranges from -128 to +127. Thus
- incrementing 127 by 1 yields -128 and thus an overflow
- error.</para>
+ <answer>
+ <para>A byte variable ranges from -128 to +127. Thus
+ incrementing 127 by 1 yields -128 and thus an overflow
+ error.</para>
- <para>Since <xref linkend="glo_Java"/> uses <link
- xlink:href="https://en.wikipedia.org/wiki/Two's_complement#firstHeading">Two's
- complement</link> representation we have:</para>
+ <para>Since <xref linkend="glo_Java"/> uses <link
+ xlink:href="https://en.wikipedia.org/wiki/Two's_complement#firstHeading">Two's
+ complement</link> representation we have:</para>
- <informaltable border="1">
- <tr>
- <td><code> 01111111</code></td>
+ <informaltable border="1">
+ <tr>
+ <td><code> 01111111</code></td>
- <td><code> 127</code></td>
- </tr>
+ <td><code> 127</code></td>
+ </tr>
- <tr>
- <td><code>+00000001</code></td>
+ <tr>
+ <td><code>+00000001</code></td>
- <td><code> +1</code></td>
- </tr>
+ <td><code> +1</code></td>
+ </tr>
- <tr>
- <td><code>=10000000</code></td>
+ <tr>
+ <td><code>=10000000</code></td>
- <td><code>=-128</code></td>
- </tr>
- </informaltable>
+ <td><code>=-128</code></td>
+ </tr>
+ </informaltable>
- <para>On machine level the above calculation is just an ordinary
- addition.</para>
+ <para>On machine level the above calculation is just an
+ ordinary addition.</para>
- <para>Conclusion: Watch out when doing (integer)
- arithmetic!</para>
+ <para>Conclusion: Watch out when doing (integer)
+ arithmetic!</para>
- <para>The compile time error is due to the definition of the
- <quote>+</quote> operator in Java always returning an
- <code>int</code> rather than a byte. Consider:</para>
+ <para>The compile time error is due to the definition of the
+ <quote>+</quote> operator in Java always returning an
+ <code>int</code> rather than a byte. Consider:</para>
- <programlisting language="java"> byte a = 120, b = 10;
+ <programlisting language="java"> byte a = 120, b = 10;
System.out.println(a + b);</programlisting>
- <para>This yields the expected output of 130 and corresponds to
- an <code>int</code> value.</para>
+ <para>This yields the expected output of 130 and corresponds
+ to an <code>int</code> value.</para>
- <para>If the expression <code>a + b</code> was of data type
- <code>byte</code> an arithmetic overflow as in the subsequent
- code example would occur:</para>
+ <para>If the expression <code>a + b</code> was of data type
+ <code>byte</code> an arithmetic overflow as in the subsequent
+ code example would occur:</para>
- <programlisting language="java"> byte a = 120, b = 10;
+ <programlisting language="java"> byte a = 120, b = 10;
byte sum = (byte) (a + b);
System.out.println(sum);</programlisting>
- <para>The explicit type conversion (a so called type cast or
- cast for short) forces the 4-byte integer into a one-byte
- variable <code>sum</code> thereby loosing the original value and
- returning -126 instead.</para>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
- </section>
+ <para>The explicit type conversion (a so called type cast or
+ cast for short) forces the 4-byte integer into a one-byte
+ variable <code>sum</code> thereby loosing the original value
+ and returning -126 instead.</para>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+ </section>
- <section xml:id="sw1SectAssignArithmetics">
- <title>Assignments and simple arithmetics</title>
+ <section xml:id="sw1SectAssignArithmetics">
+ <title>Assignments and simple arithmetics</title>
- <qandaset defaultlabel="qanda" xml:id="sw1QandaGuessingResults">
- <title>Guessing results</title>
+ <qandaset defaultlabel="qanda" xml:id="sw1QandaGuessingResults">
+ <title>Guessing results</title>
- <qandadiv>
- <qandaentry>
- <question>
- <para>Consider the following code segment:</para>
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>Consider the following code segment:</para>
- <programlisting language="java"> int a = 3;
+ <programlisting language="java"> int a = 3;
a++; //Incrementing a by 1 --> a==4
int b = a; // TODO
@@ -3069,57 +3092,57 @@ System.out.println("New value=" + a);</programlisting>
System.out.println("c=" + c);
System.out.println("e=" + e);</programlisting>
- <para>We want to guess the expected result. Copy/paste the above
- code into a main() method body within your IDE of choice
- (probably Eclipse). Though it is tempting to just execute this
- code ant watch the results <emphasis role="bold">please refrain
- from doing so!</emphasis></para>
+ <para>We want to guess the expected result. Copy/paste the
+ above code into a main() method body within your IDE of choice
+ (probably Eclipse). Though it is tempting to just execute this
+ code ant watch the results <emphasis role="bold">please
+ refrain from doing so!</emphasis></para>
- <para>Instead start a <quote>dry run</quote> complete the above
- comments to predict the expected outcome:</para>
+ <para>Instead start a <quote>dry run</quote> complete the
+ above comments to predict the expected outcome:</para>
- <para><computeroutput>a=...</computeroutput></para>
+ <para><computeroutput>a=...</computeroutput></para>
- <para><computeroutput>b=...</computeroutput></para>
+ <para><computeroutput>b=...</computeroutput></para>
- <para><computeroutput>c=...</computeroutput></para>
+ <para><computeroutput>c=...</computeroutput></para>
- <para><computeroutput>e=...</computeroutput></para>
+ <para><computeroutput>e=...</computeroutput></para>
- <para>After finishing your guesses execute your code and start
- wailing about your success rate.</para>
+ <para>After finishing your guesses execute your code and start
+ wailing about your success rate.</para>
- <tip>
- <para>Both <code>x++</code> (postfix notation) and
- <code>++x</code> (infix notation) are expressions themselves
- which might even be rewritten as <code>(x++)</code> and
- <code>(++x)</code> for the sake of clarity. The difference is
- not about operator precedence rules but simply about the
- values of these expressions when being assigned to other
- variables.</para>
- </tip>
- </question>
+ <tip>
+ <para>Both <code>x++</code> (postfix notation) and
+ <code>++x</code> (infix notation) are expressions themselves
+ which might even be rewritten as <code>(x++)</code> and
+ <code>(++x)</code> for the sake of clarity. The difference
+ is not about operator precedence rules but simply about the
+ values of these expressions when being assigned to other
+ variables.</para>
+ </tip>
+ </question>
- <answer>
- <para>As inferred by the hint the biggest problem is about
- understanding postfix and infix notation of the operators
- <code>++</code> and <code>--</code>. A corresponding expression
- evaluates to:</para>
+ <answer>
+ <para>As inferred by the hint the biggest problem is about
+ understanding postfix and infix notation of the operators
+ <code>++</code> and <code>--</code>. A corresponding
+ expression evaluates to:</para>
- <itemizedlist>
- <listitem>
- <para><code>a = x++</code> yields a ==x</para>
- </listitem>
+ <itemizedlist>
+ <listitem>
+ <para><code>a = x++</code> yields a ==x</para>
+ </listitem>
- <listitem>
- <para><code>a = ++x</code> yields a ==(x + 1)</para>
- </listitem>
- </itemizedlist>
+ <listitem>
+ <para><code>a = ++x</code> yields a ==(x + 1)</para>
+ </listitem>
+ </itemizedlist>
- <para>The rest is just obeying the <quote>due diligence</quote>
- rule set:</para>
+ <para>The rest is just obeying the <quote>due
+ diligence</quote> rule set:</para>
- <programlisting language="java"> int a = 3;
+ <programlisting language="java"> int a = 3;
a++; //Incrementing a by 1 --> a==4
int b = a; // Assigning value of a --> b==4
@@ -3138,39 +3161,39 @@ System.out.println("New value=" + a);</programlisting>
System.out.println("b=" + b);
System.out.println("c=" + c);
System.out.println("e=" + e);</programlisting>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+ </section>
</section>
- </section>
- <section xml:id="sw1StringLiterals">
- <title>Dealing with strings</title>
+ <section xml:id="sw1StringLiterals">
+ <title>Dealing with strings</title>
- <qandaset defaultlabel="qanda" xml:id="sw1QandaStringVariableMix">
- <title>Composing strings of literals and variables</title>
+ <qandaset defaultlabel="qanda" xml:id="sw1QandaStringVariableMix">
+ <title>Composing strings of literals and variables</title>
- <qandadiv>
- <qandaentry>
- <question>
- <para>Consider the following code:</para>
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>Consider the following code:</para>
- <programlisting language="java"> public static void main(String[] args) {
+ <programlisting language="java"> public static void main(String[] args) {
final int games = 3, playersPerGame = 22;
// ToDo ...
}</programlisting>
- <para>Complete the above snippet to produce the following
- output:</para>
+ <para>Complete the above snippet to produce the following
+ output:</para>
- <programlisting language="none">3 Games having 22 players each results in 66 players altogether.</programlisting>
- </question>
+ <programlisting language="none">3 Games having 22 players each results in 66 players altogether.</programlisting>
+ </question>
- <answer>
- <programlisting language="java"> public static void main(String[] args) {
+ <answer>
+ <programlisting language="java"> public static void main(String[] args) {
final int games = 3, playersPerGame = 22;
System.out.println(games + " Games having " + playersPerGame
@@ -3178,113 +3201,113 @@ System.out.println("New value=" + a);</programlisting>
+ " players altogether.");
}</programlisting>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
- <qandaset defaultlabel="qanda" xml:id="sw1QandaStringEscapeDoubleQuote">
- <title>Escaping double quotes</title>
+ <qandaset defaultlabel="qanda" xml:id="sw1QandaStringEscapeDoubleQuote">
+ <title>Escaping double quotes</title>
- <qandadiv>
- <qandaentry>
- <question>
- <para>Consider the following code:</para>
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>Consider the following code:</para>
- <programlisting language="java">public static void main(String[] args) {
+ <programlisting language="java">public static void main(String[] args) {
System.out.println("Some 'special' words.");
}</programlisting>
- <para>The corresponding output will be <computeroutput>Some
- 'special' words.</computeroutput>. Change the above code to
- replace the single quotes by double quotes producing the output
- <computeroutput>Some "special" words.</computeroutput>
- instead.</para>
-
- <tip>
- <para>Hunt for <quote>java escape double quote</quote> and read
- about <link
- xlink:href="https://proquest.safaribooksonline.com/book/programming/java/9780992133047/chapter-2-language-fundamentals/toc6_html_2#readertoolbar2">character
- literals</link>.</para>
- </tip>
- </question>
-
- <answer>
- <para>There are at least two solutions on offer:</para>
-
- <glosslist>
- <glossentry>
- <glossterm>Perfectly obvious</glossterm>
-
- <glossdef>
- <para>Inside a string literal the string terminating
- character (") may be escaped using backslashes:</para>
-
- <programlisting language="java">System.out.println("Some \"special\" words.");</programlisting>
- </glossdef>
- </glossentry>
-
- <glossentry>
- <glossterm>Even more clumsy</glossterm>
-
- <glossdef>
- <para>Double quotes may be also represented by their char
- (not string!) literal:</para>
-
- <programlisting language="java">System.out.println("Some " + '"' + "special" + '"' + " words.");</programlisting>
- </glossdef>
- </glossentry>
- </glosslist>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
-
- <qandaset defaultlabel="qanda" xml:id="sw1QandaStringSuppExercise">
- <title>Supplementary string exercises</title>
-
- <qandadiv>
- <qandaentry>
- <question>
- <para xml:id="sw1QandaStringCodingBatExtra">Solve the following
- external exercises:</para>
-
- <itemizedlist>
- <listitem>
- <para
- xlink:href="http://codingbat.com/prob/p171896">helloName</para>
- </listitem>
-
- <listitem>
- <para
- xlink:href="http://codingbat.com/prob/p161056">makeAbba</para>
- </listitem>
-
- <listitem>
- <para
- xlink:href="http://codingbat.com/prob/p147483">makeTags</para>
- </listitem>
- </itemizedlist>
- </question>
- </qandaentry>
- </qandadiv>
- </qandaset>
- </section>
+ <para>The corresponding output will be <computeroutput>Some
+ 'special' words.</computeroutput>. Change the above code to
+ replace the single quotes by double quotes producing the output
+ <computeroutput>Some "special" words.</computeroutput>
+ instead.</para>
+
+ <tip>
+ <para>Hunt for <quote>java escape double quote</quote> and
+ read about <link
+ xlink:href="https://proquest.safaribooksonline.com/book/programming/java/9780992133047/chapter-2-language-fundamentals/toc6_html_2#readertoolbar2">character
+ literals</link>.</para>
+ </tip>
+ </question>
+
+ <answer>
+ <para>There are at least two solutions on offer:</para>
+
+ <glosslist>
+ <glossentry>
+ <glossterm>Perfectly obvious</glossterm>
+
+ <glossdef>
+ <para>Inside a string literal the string terminating
+ character (") may be escaped using backslashes:</para>
+
+ <programlisting language="java">System.out.println("Some \"special\" words.");</programlisting>
+ </glossdef>
+ </glossentry>
+
+ <glossentry>
+ <glossterm>Even more clumsy</glossterm>
+
+ <glossdef>
+ <para>Double quotes may be also represented by their char
+ (not string!) literal:</para>
+
+ <programlisting language="java">System.out.println("Some " + '"' + "special" + '"' + " words.");</programlisting>
+ </glossdef>
+ </glossentry>
+ </glosslist>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+
+ <qandaset defaultlabel="qanda" xml:id="sw1QandaStringSuppExercise">
+ <title>Supplementary string exercises</title>
+
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para xml:id="sw1QandaStringCodingBatExtra">Solve the following
+ external exercises:</para>
+
+ <itemizedlist>
+ <listitem>
+ <para
+ xlink:href="http://codingbat.com/prob/p171896">helloName</para>
+ </listitem>
+
+ <listitem>
+ <para
+ xlink:href="http://codingbat.com/prob/p161056">makeAbba</para>
+ </listitem>
+
+ <listitem>
+ <para
+ xlink:href="http://codingbat.com/prob/p147483">makeTags</para>
+ </listitem>
+ </itemizedlist>
+ </question>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+ </section>
- <section xml:id="sw1LanguageFundamentalUsingFinal">
- <title>Using <code>final</code></title>
+ <section xml:id="sw1LanguageFundamentalUsingFinal">
+ <title>Using <code>final</code></title>
- <qandaset defaultlabel="qanda" xml:id="sw1QandaCircleAreaFinal">
- <title>Calculating the area of a circle avoiding accidental
- redefinition</title>
+ <qandaset defaultlabel="qanda" xml:id="sw1QandaCircleAreaFinal">
+ <title>Calculating the area of a circle avoiding accidental
+ redefinition</title>
- <qandadiv>
- <qandaentry>
- <question>
- <para>In Exercise <xref linkend="sd1SectCircleArea"/> you
- calculated a given circle's area:</para>
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>In Exercise <xref linkend="sd1SectCircleArea"/> you
+ calculated a given circle's area:</para>
- <programlisting language="java"> public static void main(String[] args) {
+ <programlisting language="java"> public static void main(String[] args) {
double radius = 2.31; // A circle having a radius (given e.g. in mm).
double pi = 3.1415926; // Constant relating a circle's radius, perimeter
@@ -3294,11 +3317,11 @@ System.out.println("New value=" + a);</programlisting>
System.out.println(area);
}</programlisting>
- <para>Though there is nothing wrong with this approach it actually
- is error prone: A careless programmer may accidentally redefine
- the value of <code>pi</code>:</para>
+ <para>Though there is nothing wrong with this approach it
+ actually is error prone: A careless programmer may accidentally
+ redefine the value of <code>pi</code>:</para>
- <programlisting language="java"> public static void main(String[] args) {
+ <programlisting language="java"> public static void main(String[] args) {
double radius = 2.31; // A circle having a radius (given e.g. in mm).
double pi = 3.1415926; // Constant relating a circle's radius, perimeter
@@ -3316,21 +3339,22 @@ System.out.println("New value=" + a);</programlisting>
System.out.println(area);
}</programlisting>
- <para>Modify the original code to avoid this type of error.</para>
+ <para>Modify the original code to avoid this type of
+ error.</para>
- <tip>
- <para>You may want to read the <quote
- xlink:href="https://proquest.safaribooksonline.com/9780992133047/toc5_html_2">Constants</quote>
- section of <xref linkend="bib_Kurniawan2015"/>.</para>
- </tip>
- </question>
+ <tip>
+ <para>You may want to read the <quote
+ xlink:href="https://proquest.safaribooksonline.com/9780992133047/toc5_html_2">Constants</quote>
+ section of <xref linkend="bib_Kurniawan2015"/>.</para>
+ </tip>
+ </question>
- <answer>
- <para>The solution is straightforward. We add the
- <code>final</code> modifier to the definition of our variable
- <code>pi</code>:</para>
+ <answer>
+ <para>The solution is straightforward. We add the
+ <code>final</code> modifier to the definition of our variable
+ <code>pi</code>:</para>
- <programlisting language="java" linenumbering="numbered">public static void main(String[] args) {
+ <programlisting language="java" linenumbering="numbered">public static void main(String[] args) {
double radius = 2.31; // A circle's radius (given e.g. in mm).
<emphasis role="bold">final</emphasis> double pi = 3.1415926; // Creating pi as a constant (non-modifiable/
@@ -3348,36 +3372,36 @@ System.out.println("New value=" + a);</programlisting>
System.out.println(area);
}</programlisting>
- <para>Now our flawed assignment at line 9 will be flagged as a
- compile time error:</para>
+ <para>Now our flawed assignment at line 9 will be flagged as a
+ compile time error:</para>
- <para><computeroutput>The final local variable pi cannot be
- assigned. It must be blank and not using a compound
- assignment</computeroutput></para>
+ <para><computeroutput>The final local variable pi cannot be
+ assigned. It must be blank and not using a compound
+ assignment</computeroutput></para>
- <para>Note the second <code>final</code> modification in the
- definition of our variable <code>area</code> to avoid erroneous
- redefinitions as well.</para>
+ <para>Note the second <code>final</code> modification in the
+ definition of our variable <code>area</code> to avoid erroneous
+ redefinitions as well.</para>
- <para>As a rule of thumb: Whenever you intend a variable not to
- change after an initial assignment use <code>final</code>
- declaring it to remain constant.</para>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
- </section>
+ <para>As a rule of thumb: Whenever you intend a variable not to
+ change after an initial assignment use <code>final</code>
+ declaring it to remain constant.</para>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+ </section>
- <section xml:id="sd1fundamentalsWildThings">
- <title>Wild things</title>
+ <section xml:id="sd1fundamentalsWildThings">
+ <title>Wild things</title>
- <qandaset defaultlabel="qanda" xml:id="sw1QandaWild">
- <qandadiv>
- <qandaentry>
- <question>
- <para>Consider the following program:</para>
+ <qandaset defaultlabel="qanda" xml:id="sw1QandaWild">
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>Consider the following program:</para>
- <programlisting language="java"> public static void main(String[] args) {
+ <programlisting language="java"> public static void main(String[] args) {
int a = 20,
b = 3,
@@ -3387,15 +3411,16 @@ System.out.println("New value=" + a);</programlisting>
}</programlisting>
- <para>This will run smoothly producing the expected output:</para>
+ <para>This will run smoothly producing the expected
+ output:</para>
- <programlisting language="none">20 + 3 + 9 = 32</programlisting>
+ <programlisting language="none">20 + 3 + 9 = 32</programlisting>
- <para>We now prettify our variable definitions by introducing
- right aligning numbers thereby padding leading positions with
- zeros:</para>
+ <para>We now prettify our variable definitions by introducing
+ right aligning numbers thereby padding leading positions with
+ zeros:</para>
- <programlisting language="java"> public static void main(String[] args) {
+ <programlisting language="java"> public static void main(String[] args) {
int a = 20,
b = 03,
@@ -3404,58 +3429,60 @@ System.out.println("New value=" + a);</programlisting>
System.out.println(a + " + " + b + " + " + c + " = " + (a + b + c));
}</programlisting>
- <para>The above code does not compile due to the compiler error
- when defining variable <code>c</code>.</para>
+ <para>The above code does not compile due to the compiler error
+ when defining variable <code>c</code>.</para>
- <para>Explain the underlying cause of this error message. Why is
- <code>b = 03</code> just fine in contrast to <code>c = 09</code>
- ?</para>
+ <para>Explain the underlying cause of this error message. Why is
+ <code>b = 03</code> just fine in contrast to <code>c = 09</code>
+ ?</para>
- <tip>
- <para>Re-read the section on integer literal
- representations.</para>
- </tip>
- </question>
+ <tip>
+ <para>Re-read the section on integer literal
+ representations.</para>
+ </tip>
+ </question>
- <answer>
- <para>Integer literals starting with <quote>0</quote> are being
- interpreted as octal representation. Since the octal system's set
- of digits is {0,1,2,3,4,5,6,7} the value <quote>09</quote> is
- simply not valid.</para>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
+ <answer>
+ <para>Integer literals starting with <quote>0</quote> are being
+ interpreted as octal representation. Since the octal system's
+ set of digits is {0,1,2,3,4,5,6,7} the value <quote>09</quote>
+ is simply not valid.</para>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
- <qandaset defaultlabel="qanda" xml:id="sd1OctalOutput">
- <title>Strange output</title>
+ <qandaset defaultlabel="qanda" xml:id="sd1OctalOutput">
+ <title>Strange output</title>
- <qandadiv>
- <qandaentry>
- <question>
- <para>Consider the following code:</para>
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>Consider the following code:</para>
- <programlisting language="java"> public static void main(String[] args) {
+ <programlisting language="java"> public static void main(String[] args) {
int a = 041;
System.out.println("Value = " + a);
}</programlisting>
- <para>On execution we receive the output <code>Value = 33</code>.
- Explain this result</para>
- </question>
-
- <answer>
- <para>This problem is related to the previous exercise: The
- integer literal 041 defines octal representation. Changing from
- octal to decimal representation takes us to 4 * 8 + 1 = 33.</para>
-
- <para>There are 11 types of people: Those, who know can read
- binary codes, those who know what binary is and those who don't
- have a clue what binary is.</para>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
+ <para>On execution we receive the output <code>Value =
+ 33</code>. Explain this result</para>
+ </question>
+
+ <answer>
+ <para>This problem is related to the previous exercise: The
+ integer literal 041 defines octal representation. Changing from
+ octal to decimal representation takes us to 4 * 8 + 1 =
+ 33.</para>
+
+ <para>There are 11 types of people: Those, who know can read
+ binary codes, those who know what binary is and those who don't
+ have a clue what binary is.</para>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+ </section>
</section>
</chapter>
--
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