diff --git a/Doc/Sd1/languageFundamentals.xml b/Doc/Sd1/languageFundamentals.xml
index 3e8acf70744203a1c5c211c195ebde22bdcddc3a..e88e2f01f8bdd18e53284f74b9d62d5f4fa0d6c8 100644
--- a/Doc/Sd1/languageFundamentals.xml
+++ b/Doc/Sd1/languageFundamentals.xml
@@ -404,17 +404,21 @@ representation</screen></td>
<figure xml:id="sd1_fig_varDeclare">
<title>Variable declaration</title>
- <programlisting language="java">double pi;</programlisting>
+ <programlisting language="java">// Variable declaration:
+// Variable's type is double
+// Variable's name is «pi» (identifier)
+
+double pi;</programlisting>
</figure>
<para>We may assign values to variables or build expressions like <code
language="java">pi * 2.0 * 2.0</code> :</para>
<figure xml:id="sd1_fig_varDeclareAndUse">
- <title>Declare and use</title>
+ <title>Declare, assign and use</title>
<programlisting language="java">double pi; // Variable declaration
-...
+
pi = 3.1415926; // Assigning value to variable
// Print a circle's area of radius 2.0
@@ -429,8 +433,8 @@ System.out.println(pi * 2.0 * 2.0);</programlisting>
<glossterm>Separate declaration and initialization</glossterm>
<glossdef>
- <programlisting language="java">double pi; // Declaration of variable pi
-...
+ <programlisting language="java">double pi; // Declaration of variable pi
+
pi = 3.1415926; // Value assignment</programlisting>
</glossdef>
</glossentry>
@@ -491,8 +495,8 @@ int c;</programlisting>
<listitem>
<para><link linkend="sd1_sect_methods">Method</link> names, e.g.
- <methodname>public static void
- main(String[args])</methodname>.</para>
+ <methodname>public static void <emphasis
+ role="red">main</emphasis>(String [] args)</methodname>.</para>
</listitem>
</itemizedlist>
</listitem>
@@ -3690,7 +3694,7 @@ _____________________________________
<programlisting language="java">float float2Power31 = Integer.MAX_VALUE + 1f;
-float floatDoubleMAX_VALUE = 2 * float2Power31* float2Power31 - 1f; // 2^63 - 1
+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>
@@ -3711,6 +3715,206 @@ Expected value: 9223372036854775807</screen>
</imageobject>
</mediaobject>
</figure>
+
+ <qandaset defaultlabel="qanda" xml:id="sd1_qanda_floatDoubleLiteral">
+ <title><code>float</code> vs. <code>double</code></title>
+
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>We consider:</para>
+
+ <informaltable border="1">
+ <tr>
+ <th>Code</th>
+
+ <th>Output</th>
+ </tr>
+
+ <tr>
+ <td valign="top"><programlisting language="java">System.out.println( 3.14 );
+System.out.println( 3.14f );
+System.out.println( 3.14d );</programlisting></td>
+
+ <td valign="top"><screen>3.14
+3.14
+3.14</screen></td>
+ </tr>
+ </informaltable>
+
+ <para>There seems to be no difference between the three literals
+ <code language="java">3.14</code>, <code
+ language="java">3.14f</code> and <code
+ language="java">3.14d</code>. Is this actually true?</para>
+
+ <tip>
+ <para>Read the section about floating point literals in <xref
+ linkend="glo_Java"/>. Write code exhibiting possible
+ differences.</para>
+ </tip>
+ </question>
+
+ <answer>
+ <para>The System.out.println( 3.14f ) statement's output is
+ actually truncated with respect to output precision. Forcing 16
+ fractional digits to become visible reads:<informaltable
+ border="1">
+ <tr>
+ <th>Code</th>
+
+ <th>Output</th>
+ </tr>
+
+ <tr>
+ <td valign="top"><programlisting language="java">System.out.println(new DecimalFormat(
+ "#0.0000000000000000").format(3.14f));</programlisting></td>
+
+ <td valign="top"><screen>3.1400001049041750</screen></td>
+ </tr>
+ </informaltable>The value 3.1400001049041750 is the closest
+ possible approximation to 3.14 when using a <link
+ xlink:href="https://en.wikipedia.org/wiki/IEEE_754-2008_revision">4-byte
+ IEEE float</link>. A <code language="java">3.14f</code> <code
+ language="java">double</code> literal won't be exact either but
+ doubles the number of representing bytes to 8 thereby enhancing
+ its representational precision substantially. This causes
+ unexpected results:</para>
+
+ <informaltable border="1">
+ <tr>
+ <th>Code</th>
+
+ <th>Output</th>
+ </tr>
+
+ <tr>
+ <td valign="top"><programlisting language="none">System.out.println(<emphasis
+ role="red">3.14f</emphasis> - <emphasis role="red">3.14d</emphasis>);</programlisting></td>
+
+ <td valign="top"><screen>1.0490417468034252E-7</screen></td>
+ </tr>
+ </informaltable>
+
+ <para>This difference is a result of <code
+ language="java">3.14d</code> providing four additional bytes of
+ precision therefore matching the exact value of <inlineequation>
+ <m:math display="inline">
+ <m:mfrac>
+ <m:mi>314</m:mi>
+
+ <m:mi>100</m:mi>
+ </m:mfrac>
+ </m:math>
+ </inlineequation> better than <code
+ language="java">3.14f</code>.</para>
+
+ <para>Regarding types we have:</para>
+
+ <informaltable border="1">
+ <tr>
+ <th>Literal</th>
+
+ <th>Comment</th>
+ </tr>
+
+ <tr>
+ <td valign="top"><code language="java">3.14f</code></td>
+
+ <td valign="top">4-byte <code language="java">float</code>
+ literal</td>
+ </tr>
+
+ <tr>
+ <td valign="top"><code language="java">3.14d</code></td>
+
+ <td valign="top">8-byte <code language="java">double</code>
+ literal</td>
+ </tr>
+
+ <tr>
+ <td valign="top"><code language="java">3.14</code></td>
+
+ <td valign="top">Equivalent to <code
+ language="java">3.14d</code></td>
+ </tr>
+ </informaltable>
+
+ <para>Assignments to variables of type <code
+ language="java">double</code> are thus always guaranteed to
+ work:</para>
+
+ <informaltable border="1">
+ <tr>
+ <th>Code</th>
+
+ <th>Comment</th>
+ </tr>
+
+ <tr>
+ <td valign="top"><programlisting language="java">double d = 3.14f;</programlisting></td>
+
+ <td valign="top">o.K., assigning <code
+ language="java">float</code> to <code
+ language="java">double</code> (widening)</td>
+ </tr>
+
+ <tr>
+ <td valign="top"><programlisting language="java">double d = 3.14d;</programlisting></td>
+
+ <td valign="top">o.K., assigning <code
+ language="java">double</code> to <code
+ language="java">double</code></td>
+ </tr>
+
+ <tr>
+ <td valign="top"><programlisting language="java">double d = 3.14;</programlisting></td>
+
+ <td valign="top">o.K., assigning <code
+ language="java">double</code> to <code
+ language="java">double</code> as well.</td>
+ </tr>
+ </informaltable>
+
+ <para>Assignments to variables of type <code
+ language="java">float</code> may fail:</para>
+
+ <informaltable border="1">
+ <tr>
+ <th>Code</th>
+
+ <th>Comment</th>
+ </tr>
+
+ <tr>
+ <td valign="top"><programlisting language="java">float d = 3.14f;</programlisting></td>
+
+ <td valign="top">o.K., assigning <code
+ language="java">float</code> to <code
+ language="java">float</code> (widening)</td>
+ </tr>
+
+ <tr>
+ <td valign="top"><programlisting language="java"><emphasis
+ role="red">float d = 3.14d;</emphasis></programlisting></td>
+
+ <td valign="top"><emphasis role="red">Error, assigning <code
+ language="java">double</code> to <code
+ language="java">float</code></emphasis></td>
+ </tr>
+
+ <tr>
+ <td valign="top"><programlisting language="java"><emphasis
+ role="red">float d = 3.14;</emphasis></programlisting></td>
+
+ <td valign="top"><emphasis role="red">Error, assigning <code
+ language="java">double</code> to <code
+ language="java">float</code> as well.</emphasis></td>
+ </tr>
+ </informaltable>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
</section>
<section xml:id="sectConversions">