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numeric_conversion/doc/html/boost_numericconversion/bounds___traits_class.html
Matias Capeletto 35a5859da6 conversion docs fixes 
[SVN r43251]
2008-02-14 18:08:16 +00:00

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<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="boost_numericconversion.bounds___traits_class"></a><a href="bounds___traits_class.html" title="bounds&lt;&gt;
traits class">bounds&lt;&gt;
traits class</a>
</h2></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="bounds___traits_class.html#boost_numericconversion.bounds___traits_class.introduction">Introduction</a></span></dt>
<dt><span class="section"><a href="bounds___traits_class.html#boost_numericconversion.bounds___traits_class.traits_class_bounds_n_">traits
class bounds&lt;N&gt;</a></span></dt>
<dt><span class="section"><a href="bounds___traits_class.html#boost_numericconversion.bounds___traits_class.examples">Examples</a></span></dt>
</dl></div>
<div class="section" lang="en">
<div class="titlepage"><div><div><h3 class="title">
<a name="boost_numericconversion.bounds___traits_class.introduction"></a><a href="bounds___traits_class.html#boost_numericconversion.bounds___traits_class.introduction" title="Introduction">Introduction</a>
</h3></div></div></div>
<p>
To determine the ranges of numeric types with <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">numeric_limits</span></code>
[18.2.1], different syntax have to be used depending on numeric type. Specifically,
<code class="computeroutput"><span class="identifier">numeric_limits</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">min</span><span class="special">()</span></code> for
integral types returns the minimum finite value, whereas for floating point
types it returns the minimum positive normalized value. The difference in
semantics makes client code unnecessarily complex and error prone.
</p>
<p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">numeric</span><span class="special">::</span><span class="identifier">bounds</span><span class="special">&lt;&gt;</span></code>
provides a consistent interface for retrieving the maximum finite value,
the minimum finite value and the minimum positive normalized value (0 for
integral types) for numeric types. The selection of implementation is performed
at compile time, so there is no runtime overhead.
</p>
</div>
<div class="section" lang="en">
<div class="titlepage"><div><div><h3 class="title">
<a name="boost_numericconversion.bounds___traits_class.traits_class_bounds_n_"></a><a href="bounds___traits_class.html#boost_numericconversion.bounds___traits_class.traits_class_bounds_n_" title="traits
class bounds&lt;N&gt;">traits
class bounds&lt;N&gt;</a>
</h3></div></div></div>
<pre class="programlisting">
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">N</span><span class="special">&gt;</span>
<span class="keyword">struct</span> <span class="identifier">bounds</span>
<span class="special">{</span>
<span class="keyword">static</span> <span class="identifier">N</span> <span class="identifier">lowest</span> <span class="special">()</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">implementation_defined</span><span class="special">;</span> <span class="special">}</span>
<span class="keyword">static</span> <span class="identifier">N</span> <span class="identifier">highest</span> <span class="special">()</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">implementation_defined</span><span class="special">;</span> <span class="special">}</span>
<span class="keyword">static</span> <span class="identifier">N</span> <span class="identifier">smallest</span><span class="special">()</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">implementation_defined</span><span class="special">;</span> <span class="special">}</span>
<span class="special">};</span>
</pre>
<a name="boost_numericconversion.bounds___traits_class.traits_class_bounds_n_.members"></a><h5>
<a name="id2626382"></a>
<a href="bounds___traits_class.html#boost_numericconversion.bounds___traits_class.traits_class_bounds_n_.members">Members</a>
</h5>
<div class="blockquote"><blockquote class="blockquote">
<p>
</p>
<p>
<code class="computeroutput"><span class="identifier">lowest</span><span class="special">()</span></code>
</p>
<p>
</p>
</blockquote></div>
<p>
Returns the minimum finite value, equivalent to <code class="computeroutput"><span class="identifier">numeric_limits</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">min</span><span class="special">()</span></code> when
<code class="computeroutput"><span class="identifier">T</span></code> is an integral type, and
to <code class="computeroutput"><span class="special">-</span><span class="identifier">numeric_limits</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">max</span><span class="special">()</span></code> when
<code class="computeroutput"><span class="identifier">T</span></code> is a floating point type.
</p>
<div class="blockquote"><blockquote class="blockquote">
<p>
</p>
<p>
<code class="computeroutput"><span class="identifier">highest</span><span class="special">()</span></code>
</p>
<p>
</p>
</blockquote></div>
<p>
Returns the maximum finite value, equivalent to <code class="computeroutput"><span class="identifier">numeric_limits</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">max</span><span class="special">()</span></code>.
</p>
<div class="blockquote"><blockquote class="blockquote">
<p>
</p>
<p>
<code class="computeroutput"><span class="identifier">smallest</span><span class="special">()</span></code>
</p>
<p>
</p>
</blockquote></div>
<p>
Returns the smallest positive normalized value for floating point types with
denormalization, or returns 0 for integral types.
</p>
</div>
<div class="section" lang="en">
<div class="titlepage"><div><div><h3 class="title">
<a name="boost_numericconversion.bounds___traits_class.examples"></a><a href="bounds___traits_class.html#boost_numericconversion.bounds___traits_class.examples" title="Examples">Examples</a>
</h3></div></div></div>
<p>
The following example demonstrates the use of <code class="computeroutput"><span class="identifier">numeric</span><span class="special">::</span><span class="identifier">bounds</span><span class="special">&lt;&gt;</span></code> and the equivalent code using <code class="computeroutput"><span class="identifier">numeric_limits</span></code>:
</p>
<pre class="programlisting">
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">iostream</span><span class="special">&gt;</span>
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">numeric</span><span class="special">/</span><span class="identifier">conversion</span><span class="special">/</span><span class="identifier">bounds</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">limits</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
<span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> <span class="special">{</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"numeric::bounds versus numeric_limits example.\n"</span><span class="special">;</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"The maximum value for float:\n"</span><span class="special">;</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">numeric</span><span class="special">::</span><span class="identifier">bounds</span><span class="special">&lt;</span><span class="keyword">float</span><span class="special">&gt;::</span><span class="identifier">highest</span><span class="special">()</span> <span class="special">&lt;&lt;</span> <span class="string">"\n"</span><span class="special">;</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">numeric_limits</span><span class="special">&lt;</span><span class="keyword">float</span><span class="special">&gt;::</span><span class="identifier">max</span><span class="special">()</span> <span class="special">&lt;&lt;</span> <span class="string">"\n"</span><span class="special">;</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"The minimum value for float:\n"</span><span class="special">;</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">numeric</span><span class="special">::</span><span class="identifier">bounds</span><span class="special">&lt;</span><span class="keyword">float</span><span class="special">&gt;::</span><span class="identifier">lowest</span><span class="special">()</span> <span class="special">&lt;&lt;</span> <span class="string">"\n"</span><span class="special">;</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="special">-</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">numeric_limits</span><span class="special">&lt;</span><span class="keyword">float</span><span class="special">&gt;::</span><span class="identifier">max</span><span class="special">()</span> <span class="special">&lt;&lt;</span> <span class="string">"\n"</span><span class="special">;</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"The smallest positive value for float:\n"</span><span class="special">;</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">numeric</span><span class="special">::</span><span class="identifier">bounds</span><span class="special">&lt;</span><span class="keyword">float</span><span class="special">&gt;::</span><span class="identifier">smallest</span><span class="special">()</span> <span class="special">&lt;&lt;</span> <span class="string">"\n"</span><span class="special">;</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">numeric_limits</span><span class="special">&lt;</span><span class="keyword">float</span><span class="special">&gt;::</span><span class="identifier">min</span><span class="special">()</span> <span class="special">&lt;&lt;</span> <span class="string">"\n"</span><span class="special">;</span>
<span class="keyword">return</span> <span class="number">0</span><span class="special">;</span>
<span class="special">}</span>
</pre>
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Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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