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10<title>The MPL Reference Manual: advance</title>
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13<body class="docframe refmanual">
14<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>&nbsp;<a href="./distance.html" class="navigation-link">Next</a></span><span class="navigation-group-separator">&nbsp;|&nbsp;</span><span class="navigation-group">Back&nbsp;<a href="./distance.html" class="navigation-link">Along</a></span><span class="navigation-group-separator">&nbsp;|&nbsp;</span><span class="navigation-group"><a href="./iterator-metafunctions.html" class="navigation-link">Up</a>&nbsp;<a href="../refmanual.html" class="navigation-link">Home</a></span><span class="navigation-group-separator">&nbsp;|&nbsp;</span><span class="navigation-group"><a href="./refmanual_toc.html" class="navigation-link">Full TOC</a></span></td>
15<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>
16</tr></table><div class="header-separator"></div>
17<div class="section" id="advance">
18<h1><a class="toc-backref" href="./iterator-metafunctions.html#id382" name="advance">advance</a></h1>
19<div class="section" id="advance-synopsis">
20<h3><a class="subsection-title" href="#synopsis" name="synopsis">Synopsis</a></h3>
21<pre class="literal-block">
22template&lt;
23      typename Iterator
24    , typename N
25    &gt;
26struct <a href="./advance.html" class="identifier">advance</a>
27{
28    typedef <em>unspecified</em> type;
29};
30</pre>
31</div>
32<div class="section" id="advance-description">
33<h3><a class="subsection-title" href="#description" name="description">Description</a></h3>
34<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" href="./bidirectional-iterator.html">bidirectional</a> and
35<a class="reference" href="./random-access-iterator.html">random access</a> iterators, the distance may be negative.</p>
36</div>
37<div class="section" id="advance-header">
38<h3><a class="subsection-title" href="#header" name="header">Header</a></h3>
39<pre class="literal-block">
40#include &lt;<a href="../../../../boost/mpl/advance.hpp" class="header">boost/mpl/advance.hpp</a>&gt;
41</pre>
42</div>
43<div class="section" id="advance-parameters">
44<h3><a class="subsection-title" href="#parameters" name="parameters">Parameters</a></h3>
45<table border="1" class="table">
46<colgroup>
47<col width="19%" />
48<col width="35%" />
49<col width="45%" />
50</colgroup>
51<thead valign="bottom">
52<tr><th>Parameter</th>
53<th>Requirement</th>
54<th>Description</th>
55</tr>
56</thead>
57<tbody valign="top">
58<tr><td><tt class="literal"><span class="pre">Iterator</span></tt></td>
59<td><a class="reference" href="./forward-iterator.html">Forward Iterator</a></td>
60<td>An iterator to advance.</td>
61</tr>
62<tr><td><tt class="literal"><span class="pre">N</span></tt></td>
63<td><a class="reference" href="./integral-constant.html">Integral Constant</a></td>
64<td>A distance.</td>
65</tr>
66</tbody>
67</table>
68</div>
69<div class="section" id="advance-model-of">
70<h3><a class="subsection-title" href="#model-of" name="model-of">Model Of</a></h3>
71<p><a class="reference" href="./tag-dispatched.html">Tag Dispatched Metafunction</a></p>
72</div>
73<div class="section" id="advance-expression-semantics">
74<h3><a class="subsection-title" href="#expression-semantics" name="expression-semantics">Expression semantics</a></h3>
75<p>For a <a class="reference" href="./forward-iterator.html">Forward Iterator</a> <tt class="literal"><span class="pre">iter</span></tt> and arbitrary <a class="reference" href="./integral-constant.html">Integral Constant</a> <tt class="literal"><span class="pre">n</span></tt>:</p>
76<pre class="literal-block">
77typedef <a href="./advance.html" class="identifier">advance</a>&lt;iter,n&gt;::type j;
78</pre>
79<table class="field-list" frame="void" rules="none">
80<col class="field-name" />
81<col class="field-body" />
82<tbody valign="top">
83<tr class="field"><th class="field-name">Return type:</th><td class="field-body"><a class="reference" href="./forward-iterator.html">Forward Iterator</a>.</td>
84</tr>
85<tr class="field"><th class="field-name">Precondition:</th><td class="field-body">If <tt class="literal"><span class="pre">Iterator</span></tt> is a <a class="reference" href="./forward-iterator.html">Forward Iterator</a>, <tt class="literal"><span class="pre">n::value</span></tt> must be nonnegative.</td>
86</tr>
87<tr class="field"><th class="field-name">Semantics:</th><td class="field-body"><p class="first">Equivalent to:</p>
88<pre class="literal-block">
89typedef iter i0;
90typedef <a href="./next.html" class="identifier">next</a>&lt;i0&gt;::type i1;
91<em>...</em>
92typedef <a href="./next.html" class="identifier">next</a>&lt;i<em>n-1</em>&gt;::type j;
93</pre>
94<p>if <tt class="literal"><span class="pre">n::value</span> <span class="pre">&gt;</span> <span class="pre">0</span></tt>, and</p>
95<pre class="literal-block">
96typedef iter i0;
97typedef <a href="./prior.html" class="identifier">prior</a>&lt;i0&gt;::type i1;
98<em>...</em>
99typedef <a href="./prior.html" class="identifier">prior</a>&lt;i<em>n-1</em>&gt;::type j;
100</pre>
101<p class="last">otherwise.</p>
102</td>
103</tr>
104<tr class="field"><th class="field-name">Postcondition:</th><td class="field-body"><tt class="literal"><span class="pre">j</span></tt> is dereferenceable or past-the-end;
105<tt class="literal"><span class="pre"><a href="./distance.html" class="identifier">distance</a>&lt;iter,j&gt;::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">&gt;</span> <span class="pre">0</span></tt>, and
106<tt class="literal"><span class="pre"><a href="./distance.html" class="identifier">distance</a>&lt;j,iter&gt;::value</span> <span class="pre">==</span> <span class="pre">n::value</span></tt> otherwise.</td>
107</tr>
108</tbody>
109</table>
110</div>
111<div class="section" id="advance-complexity">
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" href="./random-access-iterator.html">Random Access Iterator</a>, otherwise linear time.</p>
115</div>
116<div class="section" id="advance-example">
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>&lt;int,0,10&gt; numbers;
120typedef <a href="./begin.html" class="identifier">begin</a>&lt;numbers&gt;::type first;
121typedef <a href="./end.html" class="identifier">end</a>&lt;numbers&gt;::type last;
122
123typedef <a href="./advance.html" class="identifier">advance</a>&lt;first,<a href="./int.html" class="identifier">int_</a>&lt;10&gt; &gt;::type i1;
124typedef <a href="./advance.html" class="identifier">advance</a>&lt;last,<a href="./int.html" class="identifier">int_</a>&lt;-10&gt; &gt;::type i2;
125
126<a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( boost::is_same&lt;i1,last&gt; ));
127<a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( boost::is_same&lt;i2,first&gt; ));
128</pre>
129</div>
130<div class="section" id="advance-see-also">
131<h3><a class="subsection-title" href="#see-also" name="see-also">See also</a></h3>
132<p><a class="reference" href="./iterators.html">Iterators</a>, <a class="reference" href="./tag-dispatched.html">Tag Dispatched Metafunction</a>, <a class="refentry reference" href="./distance.html"><tt class="refentry literal"><span class="pre">distance</span></tt></a>, <a class="refentry reference" href="./next.html"><tt class="refentry literal"><span class="pre">next</span></tt></a></p>
133<!-- modtime: November 11, 2004 11:16:39 +0000 -->
134<!-- Iterators/Iterator Metafunctions//distance |20 -->
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137
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