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- <div class="titlepage"><div><div><h2 class="title" style="clear: both">
- <a name="boost_numericconversion.bounds___traits_class"></a><a class="link" href="bounds___traits_class.html" title="bounds<> traits class">bounds<>
- traits class</a>
- </h2></div></div></div>
- <div class="toc"><dl class="toc">
- <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<N></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">
- <div class="titlepage"><div><div><h3 class="title">
- <a name="boost_numericconversion.bounds___traits_class.introduction"></a><a class="link" 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"><</span><span class="identifier">T</span><span class="special">>::</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"><></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">
- <div class="titlepage"><div><div><h3 class="title">
- <a name="boost_numericconversion.bounds___traits_class.traits_class_bounds_n_"></a><a class="link" href="bounds___traits_class.html#boost_numericconversion.bounds___traits_class.traits_class_bounds_n_" title="traits class bounds<N>">traits
- class bounds<N></a>
- </h3></div></div></div>
- <pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">N</span><span class="special">></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>
- <h5>
- <a name="boost_numericconversion.bounds___traits_class.traits_class_bounds_n_.h0"></a>
- <span class="phrase"><a name="boost_numericconversion.bounds___traits_class.traits_class_bounds_n_.members"></a></span><a class="link" 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>
- <code class="computeroutput"><span class="identifier">lowest</span><span class="special">()</span></code>
- </p></blockquote></div>
- <p>
- Returns the minimum finite value, equivalent to <code class="computeroutput"><span class="identifier">numeric_limits</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</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"><</span><span class="identifier">T</span><span class="special">>::</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>
- <code class="computeroutput"><span class="identifier">highest</span><span class="special">()</span></code>
- </p></blockquote></div>
- <p>
- Returns the maximum finite value, equivalent to <code class="computeroutput"><span class="identifier">numeric_limits</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">max</span><span class="special">()</span></code>.
- </p>
- <div class="blockquote"><blockquote class="blockquote"><p>
- <code class="computeroutput"><span class="identifier">smallest</span><span class="special">()</span></code>
- </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">
- <div class="titlepage"><div><div><h3 class="title">
- <a name="boost_numericconversion.bounds___traits_class.examples"></a><a class="link" 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"><></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"><</span><span class="identifier">iostream</span><span class="special">></span>
- <span class="preprocessor">#include</span> <span class="special"><</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">></span>
- <span class="preprocessor">#include</span> <span class="special"><</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">></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"><<</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"><<</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"><<</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"><</span><span class="keyword">float</span><span class="special">>::</span><span class="identifier">highest</span><span class="special">()</span> <span class="special"><<</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"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">numeric_limits</span><span class="special"><</span><span class="keyword">float</span><span class="special">>::</span><span class="identifier">max</span><span class="special">()</span> <span class="special"><<</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"><<</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"><<</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"><</span><span class="keyword">float</span><span class="special">>::</span><span class="identifier">lowest</span><span class="special">()</span> <span class="special"><<</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"><<</span> <span class="special">-</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">numeric_limits</span><span class="special"><</span><span class="keyword">float</span><span class="special">>::</span><span class="identifier">max</span><span class="special">()</span> <span class="special"><<</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"><<</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"><<</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"><</span><span class="keyword">float</span><span class="special">>::</span><span class="identifier">smallest</span><span class="special">()</span> <span class="special"><<</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"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">numeric_limits</span><span class="special"><</span><span class="keyword">float</span><span class="special">>::</span><span class="identifier">min</span><span class="special">()</span> <span class="special"><<</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>
- </div>
- </div>
- <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
- <td align="left"></td>
- <td align="right"><div class="copyright-footer">Copyright © 2004-2007 Fernando
- Luis Cacciola Carballal<p>
- 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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