From 4c13972c5b0c8a7997b536734260dd65424029d9 Mon Sep 17 00:00:00 2001
From: Martin Goik <goik@hdm-stuttgart.de>
Date: Sun, 22 Mar 2015 21:56:48 +0100
Subject: [PATCH] Two octal representation examples
---
Doc/Sd1/extraExercise.xml | 6 +++
Doc/Sd1/languageFundamentals.xml | 82 ++++++++++++++++++++++++++++++++
2 files changed, 88 insertions(+)
diff --git a/Doc/Sd1/extraExercise.xml b/Doc/Sd1/extraExercise.xml
index 7160f239a..c9712eb2d 100644
--- a/Doc/Sd1/extraExercise.xml
+++ b/Doc/Sd1/extraExercise.xml
@@ -27,6 +27,12 @@
xlink:href="https://projecteuler.net/problem=1">1</link>, <link
xlink:href="https://projecteuler.net/problem=2">2</link>, <link
xlink:href="https://projecteuler.net/problem=4">4</link>, <link
+ xlink:href="https://projecteuler.net/problem=5">5</link>, <link
+ xlink:href="https://projecteuler.net/problem=8">8</link>, <link
+ xlink:href="https://projecteuler.net/problem=9">9</link>, <link
+ xlink:href="https://projecteuler.net/problem=1">1</link>, <link
+ xlink:href="https://projecteuler.net/problem=1">1</link>, <link
+ xlink:href="https://projecteuler.net/problem=1">1</link>, <link
xlink:href="https://projecteuler.net/problem=1">1</link>, <link
xlink:href="https://projecteuler.net/problem=1">1</link>, <link
xlink:href="https://projecteuler.net/problem=1">1</link>, <link
diff --git a/Doc/Sd1/languageFundamentals.xml b/Doc/Sd1/languageFundamentals.xml
index 106268f3e..53a203c9c 100644
--- a/Doc/Sd1/languageFundamentals.xml
+++ b/Doc/Sd1/languageFundamentals.xml
@@ -1141,4 +1141,86 @@ System.out.println("New value=" + a);</programlisting>
</qandadiv>
</qandaset>
</section>
+
+ <section xml:id="sd1fundamentalsWildThings">
+ <title>Wild things</title>
+
+ <qandaset defaultlabel="qanda" xml:id="sw1QandaWild">
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>Consider the following program:</para>
+
+ <programlisting language="java"> public static void main(String[] args) {
+
+ int a = 20,
+ b = 3,
+ c = 9;
+
+ System.out.println(a + " + " + b + " + " + c + " = " + (a + b + c));
+
+ }</programlisting>
+
+ <para>This will run smoothly producing the expected output:</para>
+
+ <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>
+
+ <programlisting language="java"> public static void main(String[] args) {
+
+ int a = 20,
+ b = 03,
+ <emphasis role="bold">c = 09; // Compiler error: The literal 09 of type int is out of range</emphasis>
+
+ 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>Explain the underlying cause of this error message. Why is
+ <code>b = 03</code> just fine in contrast to <code>c = 09</code>
+ ?</para>
+ </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>
+
+ <qandaset defaultlabel="qanda" xml:id="sd1OctalOutput">
+ <title>Strange output</title>
+
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>Consider the following code:</para>
+
+ <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>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+ </section>
</chapter>
--
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