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| 24 | </div> | |
| 25 | <div class="section"> | |
| 26 | <div class="titlepage"><div><div><h2 class="title" style="clear: both"> | |
| 27 | <a name="boost_numericconversion.bounds___traits_class"></a><a class="link" href="bounds___traits_class.html" title="bounds<> traits class">bounds<> | |
| 28 | traits class</a> | |
| 29 | </h2></div></div></div> | |
| 30 | <div class="toc"><dl class="toc"> | |
| 31 | <dt><span class="section"><a href="bounds___traits_class.html#boost_numericconversion.bounds___traits_class.introduction">Introduction</a></span></dt> | |
| 32 | <dt><span class="section"><a href="bounds___traits_class.html#boost_numericconversion.bounds___traits_class.traits_class_bounds_n_">traits | |
| 33 | class bounds<N></a></span></dt> | |
| 34 | <dt><span class="section"><a href="bounds___traits_class.html#boost_numericconversion.bounds___traits_class.examples">Examples</a></span></dt> | |
| 35 | </dl></div> | |
| 36 | <div class="section"> | |
| 37 | <div class="titlepage"><div><div><h3 class="title"> | |
| 38 | <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> | |
| 39 | </h3></div></div></div> | |
| 40 | <p> | |
| 41 | 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> | |
| 42 | [18.2.1], different syntax have to be used depending on numeric type. Specifically, | |
| 43 | <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 | |
| 44 | integral types returns the minimum finite value, whereas for floating point | |
| 45 | types it returns the minimum positive normalized value. The difference in | |
| 46 | semantics makes client code unnecessarily complex and error prone. | |
| 47 | </p> | |
| 48 | <p> | |
| 49 | <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> | |
| 50 | provides a consistent interface for retrieving the maximum finite value, | |
| 51 | the minimum finite value and the minimum positive normalized value (0 for | |
| 52 | integral types) for numeric types. The selection of implementation is performed | |
| 53 | at compile time, so there is no runtime overhead. | |
| 54 | </p> | |
| 55 | </div> | |
| 56 | <div class="section"> | |
| 57 | <div class="titlepage"><div><div><h3 class="title"> | |
| 58 | <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 | |
| 59 | class bounds<N></a> | |
| 60 | </h3></div></div></div> | |
| 61 | <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> | |
| 62 | <span class="keyword">struct</span> <span class="identifier">bounds</span> | |
| 63 | <span class="special">{</span> | |
| 64 | <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> | |
| 65 | <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> | |
| 66 | <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> | |
| 67 | <span class="special">};</span> | |
| 68 | </pre> | |
| 69 | <h5> | |
| 70 | <a name="boost_numericconversion.bounds___traits_class.traits_class_bounds_n_.h0"></a> | |
| 71 | <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> | |
| 72 | </h5> | |
| 73 | <div class="blockquote"><blockquote class="blockquote"><p> | |
| 74 | <code class="computeroutput"><span class="identifier">lowest</span><span class="special">()</span></code> | |
| 75 | </p></blockquote></div> | |
| 76 | <p> | |
| 77 | 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 | |
| 78 | <code class="computeroutput"><span class="identifier">T</span></code> is an integral type, and | |
| 79 | 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 | |
| 80 | <code class="computeroutput"><span class="identifier">T</span></code> is a floating point type. | |
| 81 | </p> | |
| 82 | <div class="blockquote"><blockquote class="blockquote"><p> | |
| 83 | <code class="computeroutput"><span class="identifier">highest</span><span class="special">()</span></code> | |
| 84 | </p></blockquote></div> | |
| 85 | <p> | |
| 86 | 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>. | |
| 87 | </p> | |
| 88 | <div class="blockquote"><blockquote class="blockquote"><p> | |
| 89 | <code class="computeroutput"><span class="identifier">smallest</span><span class="special">()</span></code> | |
| 90 | </p></blockquote></div> | |
| 91 | <p> | |
| 92 | Returns the smallest positive normalized value for floating point types with | |
| 93 | denormalization, or returns 0 for integral types. | |
| 94 | </p> | |
| 95 | </div> | |
| 96 | <div class="section"> | |
| 97 | <div class="titlepage"><div><div><h3 class="title"> | |
| 98 | <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> | |
| 99 | </h3></div></div></div> | |
| 100 | <p> | |
| 101 | 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>: | |
| 102 | </p> | |
| 103 | <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">iostream</span><span class="special">></span> | |
| 104 | ||
| 105 | <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> | |
| 106 | <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> | |
| 107 | ||
| 108 | <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> <span class="special">{</span> | |
| 109 | ||
| 110 | <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> | |
| 111 | ||
| 112 | <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> | |
| 113 | <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> | |
| 114 | <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> | |
| 115 | ||
| 116 | <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> | |
| 117 | <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> | |
| 118 | <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> | |
| 119 | ||
| 120 | <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> | |
| 121 | <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> | |
| 122 | <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> | |
| 123 | ||
| 124 | <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span> | |
| 125 | <span class="special">}</span> | |
| 126 | </pre> | |
| 127 | </div> | |
| 128 | </div> | |
| 129 | <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> | |
| 130 | <td align="left"></td> | |
| 131 | <td align="right"><div class="copyright-footer">Copyright © 2004-2007 Fernando | |
| 132 | Luis Cacciola Carballal<p> | |
| 133 | Distributed under the Boost Software License, Version 1.0. (See accompanying | |
| 134 | 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>) | |
| 135 | </p> | |
| 136 | </div></td> | |
| 137 | </tr></table> | |
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