ceph/src/boost/libs/mpl/doc/refmanual/distance.html

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  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="./distance.html" class="navigation-link">distance</a></td>
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  14 <div class="section" id="distance">
  15 <h1><a class="toc-backref" href="./iterator-metafunctions.html#id1455">distance</a></h1>
  16 <div class="section" id="id412">
  17 <h3><a class="subsection-title" href="#synopsis" name="synopsis">Synopsis</a></h3>
  18 <pre class="literal-block">
  19 template&lt;
  20       typename First
  21     , typename Last
  22     &gt;
  23 struct <a href="./distance.html" class="identifier">distance</a>
  24 {
  25     typedef <em>unspecified</em> type;
  26 };
  27 </pre>
  28 </div>
  29 <div class="section" id="id413">
  30 <h3><a class="subsection-title" href="#description" name="description">Description</a></h3>
  31 <p>Returns the distance between <tt class="literal"><span class="pre">First</span></tt> and <tt class="literal"><span class="pre">Last</span></tt> iterators, that is, an
  32 <a class="reference internal" href="./integral-constant.html">Integral Constant</a> <tt class="literal"><span class="pre">n</span></tt> such that <tt class="literal"><span class="pre"><a href="./advance.html" class="identifier">advance</a>&lt;First,n&gt;::type</span></tt> is
  33 identical to <tt class="literal"><span class="pre">Last</span></tt>.</p>
  34 </div>
  35 <div class="section" id="id414">
  36 <h3><a class="subsection-title" href="#header" name="header">Header</a></h3>
  37 <pre class="literal-block">
  38 #include &lt;<a href="../../../../boost/mpl/distance.hpp" class="header">boost/mpl/distance.hpp</a>&gt;
  39 </pre>
  40 </div>
  41 <div class="section" id="id415">
  42 <h3><a class="subsection-title" href="#parameters" name="parameters">Parameters</a></h3>
  43 <table border="1" class="docutils table">
  44 <colgroup>
  45 <col width="19%" />
  46 <col width="35%" />
  47 <col width="45%" />
  48 </colgroup>
  49 <thead valign="bottom">
  50 <tr><th class="head">Parameter</th>
  51 <th class="head">Requirement</th>
  52 <th class="head">Description</th>
  53 </tr>
  54 </thead>
  55 <tbody valign="top">
  56 <tr><td><tt class="literal"><span class="pre">First</span></tt>,
  57 <tt class="literal"><span class="pre">Last</span></tt></td>
  58 <td><a class="reference internal" href="./forward-iterator.html">Forward Iterator</a></td>
  59 <td>Iterators to compute a
  60 distance between.</td>
  61 </tr>
  62 </tbody>
  63 </table>
  64 </div>
  65 <div class="section" id="id416">
  66 <h3><a class="subsection-title" href="#model-of" name="model-of">Model Of</a></h3>
  67 <p><a class="reference internal" href="./tag-dispatched-metafunction.html">Tag Dispatched Metafunction</a></p>
  68 </div>
  69 <div class="section" id="id417">
  70 <h3><a class="subsection-title" href="#expression-semantics" name="expression-semantics">Expression semantics</a></h3>
  71 <p>For any <a class="reference internal" href="./forward-iterator.html">Forward Iterator</a>s <tt class="literal"><span class="pre">first</span></tt> and <tt class="literal"><span class="pre">last</span></tt>:</p>
  72 <pre class="literal-block">
  73 typedef <a href="./distance.html" class="identifier">distance</a>&lt;first,last&gt;::type n;
  74 </pre>
  75 <table class="docutils field-list" frame="void" rules="none">
  76 <col class="field-name" />
  77 <col class="field-body" />
  78 <tbody valign="top">
  79 <tr class="field"><th class="field-name">Return type:</th><td class="field-body"><p class="first"><a class="reference internal" href="./integral-constant.html">Integral Constant</a>.</p>
  80 </td>
  81 </tr>
  82 <tr class="field"><th class="field-name">Precondition:</th><td class="field-body"><p class="first">[<tt class="literal"><span class="pre">first</span></tt>, <tt class="literal"><span class="pre">last</span></tt>) is a valid range.</p>
  83 </td>
  84 </tr>
  85 <tr class="field"><th class="field-name">Semantics:</th><td class="field-body"><p class="first">Equivalent to</p>
  86 <pre class="literal-block">
  87 typedef <a href="./iter-fold.html" class="identifier">iter_fold</a>&lt;
  88       <a href="./iterator-range.html" class="identifier">iterator_range</a>&lt;first,last&gt;
  89     , <a href="./long.html" class="identifier">long_</a>&lt;0&gt;
  90     , <a href="./next.html" class="identifier">next</a>&lt;<a href="./placeholders.html" class="identifier">_1</a>&gt;
  91     &gt;::type n;
  92 </pre>
  93 </td>
  94 </tr>
  95 <tr class="field"><th class="field-name">Postcondition:</th><td class="field-body"><p class="first last"><tt class="literal"><span class="pre">is_same&lt;</span> <span class="pre"><a href="./advance.html" class="identifier">advance</a>&lt;first,n&gt;::type,</span> <span class="pre">last</span> <span class="pre">&gt;::value</span> <span class="pre">==</span> <span class="pre">true</span></tt>.</p>
  96 </td>
  97 </tr>
  98 </tbody>
  99 </table>
 100 </div>
 101 <div class="section" id="id418">
 102 <h3><a class="subsection-title" href="#complexity" name="complexity">Complexity</a></h3>
 103 <p>Amortized constant time if <tt class="literal"><span class="pre">first</span></tt> and <tt class="literal"><span class="pre">last</span></tt> are <a class="reference internal" href="./random-access-iterator.html">Random Access Iterator</a>s,
 104 otherwise linear time.</p>
 105 </div>
 106 <div class="section" id="id419">
 107 <h3><a class="subsection-title" href="#example" name="example">Example</a></h3>
 108 <pre class="literal-block">
 109 typedef <a href="./range-c.html" class="identifier">range_c</a>&lt;int,0,10&gt;::type range;
 110 typedef <a href="./begin.html" class="identifier">begin</a>&lt;range&gt;::type first;
 111 typedef <a href="./end.html" class="identifier">end</a>&lt;range&gt;::type last;
 112
 113 <a href="./assert-relation.html" class="identifier">BOOST_MPL_ASSERT_RELATION</a>( (<a href="./distance.html" class="identifier">distance</a>&lt;first,last&gt;::value), ==, 10);
 114 </pre>
 115 </div>
 116 <div class="section" id="id420">
 117 <h3><a class="subsection-title" href="#see-also" name="see-also">See also</a></h3>
 118 <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="./advance.html">advance</a>, <a class="reference internal" href="./next.html">next</a>, <a class="reference internal" href="./prior.html">prior</a></p>
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