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: advance</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="./iterator-metafunctions.html" class="navigation-link">Prev</a> <a href="./distance.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group">Back <a href="./distance.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./iterator-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="./iterators.html" class="navigation-link">Iterators</a> / <a href="./iterator-metafunctions.html" class="navigation-link">Iterator Metafunctions</a> / <a href="./advance.html" class="navigation-link">advance</a></td> 13</tr></table><div class="header-separator"></div> 14<div class="section" id="advance"> 15<h1><a class="toc-backref" href="./iterator-metafunctions.html#id1454">advance</a></h1> 16<div class="section" id="id403"> 17<h3><a class="subsection-title" href="#synopsis" name="synopsis">Synopsis</a></h3> 18<pre class="literal-block"> 19template< 20 typename Iterator 21 , typename N 22 > 23struct <a href="./advance.html" class="identifier">advance</a> 24{ 25 typedef <em>unspecified</em> type; 26}; 27</pre> 28</div> 29<div class="section" id="id404"> 30<h3><a class="subsection-title" href="#description" name="description">Description</a></h3> 31<p>Moves <tt class="literal"><span class="pre">Iterator</span></tt> by the distance <tt class="literal"><span class="pre">N</span></tt>. For <a class="reference internal" href="./bidirectional-iterator.html">bidirectional</a> and 32<a class="reference internal" href="./random-access-iterator.html">random access</a> iterators, the distance may be negative.</p> 33</div> 34<div class="section" id="id405"> 35<h3><a class="subsection-title" href="#header" name="header">Header</a></h3> 36<pre class="literal-block"> 37#include <<a href="../../../../boost/mpl/advance.hpp" class="header">boost/mpl/advance.hpp</a>> 38</pre> 39</div> 40<div class="section" id="id406"> 41<h3><a class="subsection-title" href="#parameters" name="parameters">Parameters</a></h3> 42<table border="1" class="docutils table"> 43<colgroup> 44<col width="19%" /> 45<col width="35%" /> 46<col width="45%" /> 47</colgroup> 48<thead valign="bottom"> 49<tr><th class="head">Parameter</th> 50<th class="head">Requirement</th> 51<th class="head">Description</th> 52</tr> 53</thead> 54<tbody valign="top"> 55<tr><td><tt class="literal"><span class="pre">Iterator</span></tt></td> 56<td><a class="reference internal" href="./forward-iterator.html">Forward Iterator</a></td> 57<td>An iterator to advance.</td> 58</tr> 59<tr><td><tt class="literal"><span class="pre">N</span></tt></td> 60<td><a class="reference internal" href="./integral-constant.html">Integral Constant</a></td> 61<td>A distance.</td> 62</tr> 63</tbody> 64</table> 65</div> 66<div class="section" id="id407"> 67<h3><a class="subsection-title" href="#model-of" name="model-of">Model Of</a></h3> 68<p><a class="reference internal" href="./tag-dispatched-metafunction.html">Tag Dispatched Metafunction</a></p> 69</div> 70<div class="section" id="id408"> 71<h3><a class="subsection-title" href="#expression-semantics" name="expression-semantics">Expression semantics</a></h3> 72<p>For a <a class="reference internal" href="./forward-iterator.html">Forward Iterator</a> <tt class="literal"><span class="pre">iter</span></tt> and arbitrary <a class="reference internal" href="./integral-constant.html">Integral Constant</a> <tt class="literal"><span class="pre">n</span></tt>:</p> 73<pre class="literal-block"> 74typedef <a href="./advance.html" class="identifier">advance</a><iter,n>::type j; 75</pre> 76<table class="docutils field-list" frame="void" rules="none"> 77<col class="field-name" /> 78<col class="field-body" /> 79<tbody valign="top"> 80<tr class="field"><th class="field-name">Return type:</th><td class="field-body"><p class="first"><a class="reference internal" href="./forward-iterator.html">Forward Iterator</a>.</p> 81</td> 82</tr> 83<tr class="field"><th class="field-name">Precondition:</th><td class="field-body"><p class="first">If <tt class="literal"><span class="pre">Iterator</span></tt> is a <a class="reference internal" href="./forward-iterator.html">Forward Iterator</a>, <tt class="literal"><span class="pre">n::value</span></tt> must be nonnegative.</p> 84</td> 85</tr> 86<tr class="field"><th class="field-name">Semantics:</th><td class="field-body"><p class="first">Equivalent to:</p> 87<pre class="literal-block"> 88typedef iter i0; 89typedef <a href="./next.html" class="identifier">next</a><i0>::type i1; 90<em>...</em> 91typedef <a href="./next.html" class="identifier">next</a><i<em>n-1</em>>::type j; 92</pre> 93<p>if <tt class="literal"><span class="pre">n::value</span> <span class="pre">></span> <span class="pre">0</span></tt>, and</p> 94<pre class="literal-block"> 95typedef iter i0; 96typedef <a href="./prior.html" class="identifier">prior</a><i0>::type i1; 97<em>...</em> 98typedef <a href="./prior.html" class="identifier">prior</a><i<em>n-1</em>>::type j; 99</pre> 100<p>otherwise.</p> 101</td> 102</tr> 103<tr class="field"><th class="field-name">Postcondition:</th><td class="field-body"><p class="first last"><tt class="literal"><span class="pre">j</span></tt> is dereferenceable or past-the-end; 104<tt class="literal"><span class="pre"><a href="./distance.html" class="identifier">distance</a><iter,j>::value</span> <span class="pre">==</span> <span class="pre">n::value</span></tt> if <tt class="literal"><span class="pre">n::value</span> <span class="pre">></span> <span class="pre">0</span></tt>, and 105<tt class="literal"><span class="pre"><a href="./distance.html" class="identifier">distance</a><j,iter>::value</span> <span class="pre">==</span> <span class="pre">n::value</span></tt> otherwise.</p> 106</td> 107</tr> 108</tbody> 109</table> 110</div> 111<div class="section" id="id409"> 112<h3><a class="subsection-title" href="#complexity" name="complexity">Complexity</a></h3> 113<p>Amortized constant time if <tt class="literal"><span class="pre">iter</span></tt> is a model of 114<a class="reference internal" href="./random-access-iterator.html">Random Access Iterator</a>, otherwise linear time.</p> 115</div> 116<div class="section" id="id410"> 117<h3><a class="subsection-title" href="#example" name="example">Example</a></h3> 118<pre class="literal-block"> 119typedef <a href="./range-c.html" class="identifier">range_c</a><int,0,10> numbers; 120typedef <a href="./begin.html" class="identifier">begin</a><numbers>::type first; 121typedef <a href="./end.html" class="identifier">end</a><numbers>::type last; 122 123typedef <a href="./advance.html" class="identifier">advance</a><first,<a href="./int.html" class="identifier">int_</a><10> >::type i1; 124typedef <a href="./advance.html" class="identifier">advance</a><last,<a href="./int.html" class="identifier">int_</a><-10> >::type i2; 125 126<a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( boost::is_same<i1,last> )); 127<a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( boost::is_same<i2,first> )); 128</pre> 129</div> 130<div class="section" id="id411"> 131<h3><a class="subsection-title" href="#see-also" name="see-also">See also</a></h3> 132<p><a class="reference internal" href="./iterators.html">Iterators</a>, <a class="reference internal" href="./tag-dispatched-metafunction.html">Tag Dispatched Metafunction</a>, <a class="reference internal" href="./distance.html">distance</a>, <a class="reference internal" href="./next.html">next</a></p> 133<!-- Iterators/Iterator Metafunctions//distance |20 --> 134</div> 135</div> 136 137<div class="footer-separator"></div> 138<table class="footer"><tr class="footer"><td class="header-group navigation-bar"><span class="navigation-group"><a href="./iterator-metafunctions.html" class="navigation-link">Prev</a> <a href="./distance.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group">Back <a href="./distance.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./iterator-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> 139<td><div class="copyright-footer"><div class="copyright">Copyright © 2001-2009 Aleksey Gurtovoy and David Abrahams</div> 140Distributed under the Boost Software License, Version 1.0. (See accompanying 141file 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> 142</html> 143