1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>bounds<> traits class</title> 5<link rel="stylesheet" href="../boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../index.html" title="Chapter 1. Boost.NumericConversion"> 8<link rel="up" href="../index.html" title="Chapter 1. Boost.NumericConversion"> 9<link rel="prev" href="type_requirements_and_user_defined_types_support.html" title="Type Requirements and User-defined-types support"> 10<link rel="next" href="conversion_traits___traits_class.html" title="conversion_traits<> traits class"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="type_requirements_and_user_defined_types_support.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="conversion_traits___traits_class.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 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> 138<hr> 139<div class="spirit-nav"> 140<a accesskey="p" href="type_requirements_and_user_defined_types_support.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="conversion_traits___traits_class.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 141</div> 142</body> 143</html> 144
