1<?xml version="1.0" encoding="utf-8" ?> 2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> 4<head> 5<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 6<meta name="generator" content="Docutils 0.7: http://docutils.sourceforge.net/" /> 7<title>The MPL Reference Manual: back</title> 8<link rel="stylesheet" href="../style.css" type="text/css" /> 9</head> 10<body class="docframe refmanual"> 11<table class="header"><tr class="header"><td class="header-group navigation-bar"><span class="navigation-group"><a href="./at-c.html" class="navigation-link">Prev</a> <a href="./begin.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./at-c.html" class="navigation-link">Back</a> <a href="./begin.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./intrinsic-metafunctions.html" class="navigation-link">Up</a> <a href="../refmanual.html" class="navigation-link">Home</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./refmanual_toc.html" class="navigation-link">Full TOC</a></span></td> 12<td class="header-group page-location"><a href="../refmanual.html" class="navigation-link">Front Page</a> / <a href="./sequences.html" class="navigation-link">Sequences</a> / <a href="./intrinsic-metafunctions.html" class="navigation-link">Intrinsic Metafunctions</a> / <a href="./back.html" class="navigation-link">back</a></td> 13</tr></table><div class="header-separator"></div> 14<div class="section" id="back"> 15<h1><a class="toc-backref" href="./intrinsic-metafunctions.html#id1427">back</a></h1> 16<div class="section" id="id193"> 17<h3><a class="subsection-title" href="#synopsis" name="synopsis">Synopsis</a></h3> 18<pre class="literal-block"> 19template< 20 typename Sequence 21 > 22struct <a href="./back.html" class="identifier">back</a> 23{ 24 typedef <em>unspecified</em> type; 25}; 26</pre> 27</div> 28<div class="section" id="id194"> 29<h3><a class="subsection-title" href="#description" name="description">Description</a></h3> 30<p>Returns the last element in the sequence.</p> 31</div> 32<div class="section" id="id195"> 33<h3><a class="subsection-title" href="#header" name="header">Header</a></h3> 34<pre class="literal-block"> 35#include <<a href="../../../../boost/mpl/back.hpp" class="header">boost/mpl/back.hpp</a>> 36</pre> 37</div> 38<div class="section" id="id196"> 39<h3><a class="subsection-title" href="#model-of" name="model-of">Model of</a></h3> 40<p><a class="reference internal" href="./tag-dispatched-metafunction.html">Tag Dispatched Metafunction</a></p> 41</div> 42<div class="section" id="id197"> 43<h3><a class="subsection-title" href="#parameters" name="parameters">Parameters</a></h3> 44<table border="1" class="docutils table"> 45<colgroup> 46<col width="19%" /> 47<col width="35%" /> 48<col width="45%" /> 49</colgroup> 50<thead valign="bottom"> 51<tr><th class="head">Parameter</th> 52<th class="head">Requirement</th> 53<th class="head">Description</th> 54</tr> 55</thead> 56<tbody valign="top"> 57<tr><td><tt class="literal"><span class="pre">Sequence</span></tt></td> 58<td><a class="reference internal" href="./bidirectional-sequence.html">Bidirectional Sequence</a></td> 59<td>A sequence to be examined.</td> 60</tr> 61</tbody> 62</table> 63</div> 64<div class="section" id="id198"> 65<h3><a class="subsection-title" href="#expression-semantics" name="expression-semantics">Expression semantics</a></h3> 66<p>For any <a class="reference internal" href="./bidirectional-sequence.html">Bidirectional Sequence</a> <tt class="literal"><span class="pre">s</span></tt>:</p> 67<pre class="literal-block"> 68typedef <a href="./back.html" class="identifier">back</a><s>::type t; 69</pre> 70<table class="docutils field-list" frame="void" rules="none"> 71<col class="field-name" /> 72<col class="field-body" /> 73<tbody valign="top"> 74<tr class="field"><th class="field-name">Return type:</th><td class="field-body"><p class="first">A type.</p> 75</td> 76</tr> 77<tr class="field"><th class="field-name">Precondition:</th><td class="field-body"><p class="first"><tt class="literal"><span class="pre"><a href="./empty.html" class="identifier">empty</a><s>::value</span> <span class="pre">==</span> <span class="pre">false</span></tt>.</p> 78</td> 79</tr> 80<tr class="field"><th class="field-name">Semantics:</th><td class="field-body"><p class="first">Equivalent to</p> 81<pre class="last literal-block"> 82typedef <a href="./deref.html" class="identifier">deref</a>< <a href="./prior.html" class="identifier">prior</a>< <a href="./end.html" class="identifier">end</a><s>::type >::type >::type t; 83</pre> 84</td> 85</tr> 86</tbody> 87</table> 88</div> 89<div class="section" id="id199"> 90<h3><a class="subsection-title" href="#complexity" name="complexity">Complexity</a></h3> 91<p>Amortized constant time.</p> 92</div> 93<div class="section" id="id200"> 94<h3><a class="subsection-title" href="#example" name="example">Example</a></h3> 95<pre class="literal-block"> 96typedef <a href="./range-c.html" class="identifier">range_c</a><int,0,1> range1; 97typedef <a href="./range-c.html" class="identifier">range_c</a><int,0,10> range2; 98typedef <a href="./range-c.html" class="identifier">range_c</a><int,-10,0> range3; 99 100<a href="./assert-relation.html" class="identifier">BOOST_MPL_ASSERT_RELATION</a>( <a href="./back.html" class="identifier">back</a><range1>::value, ==, 0 ); 101<a href="./assert-relation.html" class="identifier">BOOST_MPL_ASSERT_RELATION</a>( <a href="./back.html" class="identifier">back</a><range2>::value, ==, 9 ); 102<a href="./assert-relation.html" class="identifier">BOOST_MPL_ASSERT_RELATION</a>( <a href="./back.html" class="identifier">back</a><range3>::value, ==, -1 ); 103</pre> 104</div> 105<div class="section" id="id201"> 106<h3><a class="subsection-title" href="#see-also" name="see-also">See also</a></h3> 107<p><a class="reference internal" href="./bidirectional-sequence.html">Bidirectional Sequence</a>, <a class="reference internal" href="./front.html">front</a>, <a class="reference internal" href="./push-back.html">push_back</a>, <a class="reference internal" href="./end.html">end</a>, <a class="reference internal" href="./deref.html">deref</a>, <a class="reference internal" href="./at.html">at</a></p> 108<!-- Sequences/Intrinsic Metafunctions//begin --> 109</div> 110</div> 111 112<div class="footer-separator"></div> 113<table class="footer"><tr class="footer"><td class="header-group navigation-bar"><span class="navigation-group"><a href="./at-c.html" class="navigation-link">Prev</a> <a href="./begin.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./at-c.html" class="navigation-link">Back</a> <a href="./begin.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./intrinsic-metafunctions.html" class="navigation-link">Up</a> <a href="../refmanual.html" class="navigation-link">Home</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./refmanual_toc.html" class="navigation-link">Full TOC</a></span></td> 114<td><div class="copyright-footer"><div class="copyright">Copyright © 2001-2009 Aleksey Gurtovoy and David Abrahams</div> 115Distributed under the Boost Software License, Version 1.0. (See accompanying 116file LICENSE_1_0.txt or copy at <a class="reference external" href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)</div></td></tr></table></body> 117</html> 118