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  26 <div class="titlepage"><div><div><h5 class="title">
  27 <a name="fusion.algorithm.query.metafunctions.count_if"></a><a class="link" href="count_if.html" title="count_if">count_if</a>
  28 </h5></div></div></div>
  29 <h6>
  30 <a name="fusion.algorithm.query.metafunctions.count_if.h0"></a>
  31             <span><a name="fusion.algorithm.query.metafunctions.count_if.description"></a></span><a class="link" href="count_if.html#fusion.algorithm.query.metafunctions.count_if.description">Description</a>
  32           </h6>
  33 <p>
  34             A metafunction that returns the result type of <code class="computeroutput"><span class="identifier">count_if</span></code>
  35             given the sequence and predicate types.
  36           </p>
  37 <h6>
  38 <a name="fusion.algorithm.query.metafunctions.count_if.h1"></a>
  39             <span><a name="fusion.algorithm.query.metafunctions.count_if.synopsis"></a></span><a class="link" href="count_if.html#fusion.algorithm.query.metafunctions.count_if.synopsis">Synopsis</a>
  40           </h6>
  41 <pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span>
  42     <span class="keyword">typename</span> <span class="identifier">Sequence</span><span class="special">,</span>
  43     <span class="keyword">typename</span> <span class="identifier">Pred</span>
  44     <span class="special">&gt;</span>
  45 <span class="keyword">struct</span> <span class="identifier">count_if</span>
  46 <span class="special">{</span>
  47     <span class="keyword">typedef</span> <span class="keyword">int</span> <span class="identifier">type</span><span class="special">;</span>
  48 <span class="special">};</span>
  49 </pre>
  50 <div class="table">
  51 <a name="fusion.algorithm.query.metafunctions.count_if.t0"></a><p class="title"><b>Table&#160;1.63.&#160;Parameters</b></p>
  52 <div class="table-contents"><table class="table" summary="Parameters">
  53 <colgroup>
  54 <col>
  55 <col>
  56 <col>
  57 </colgroup>
  58 <thead><tr>
  59 <th>
  60                     <p>
  61                       Parameter
  62                     </p>
  63                   </th>
  64 <th>
  65                     <p>
  66                       Requirement
  67                     </p>
  68                   </th>
  69 <th>
  70                     <p>
  71                       Description
  72                     </p>
  73                   </th>
  74 </tr></thead>
  75 <tbody>
  76 <tr>
  77 <td>
  78                     <p>
  79                       <code class="computeroutput"><span class="identifier">Sequence</span></code>
  80                     </p>
  81                   </td>
  82 <td>
  83                     <p>
  84                       A model of <a class="link" href="../../../sequence/concepts/forward_sequence.html" title="Forward Sequence">Forward
  85                       Sequence</a>
  86                     </p>
  87                   </td>
  88 <td>
  89                     <p>
  90                       Operation's argument
  91                     </p>
  92                   </td>
  93 </tr>
  94 <tr>
  95 <td>
  96                     <p>
  97                       <code class="computeroutput"><span class="identifier">Pred</span></code>
  98                     </p>
  99                   </td>
 100 <td>
 101                     <p>
 102                       A unary function object
 103                     </p>
 104                   </td>
 105 <td>
 106                     <p>
 107                       Operation's argument
 108                     </p>
 109                   </td>
 110 </tr>
 111 </tbody>
 112 </table></div>
 113 </div>
 114 <br class="table-break"><h6>
 115 <a name="fusion.algorithm.query.metafunctions.count_if.h2"></a>
 116             <span><a name="fusion.algorithm.query.metafunctions.count_if.expression_semantics"></a></span><a class="link" href="count_if.html#fusion.algorithm.query.metafunctions.count_if.expression_semantics">Expression
 117             Semantics</a>
 118           </h6>
 119 <pre class="programlisting"><a class="link" href="count_if.html" title="count_if"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">count_if</span></code></a><span class="special">&lt;</span><span class="identifier">Sequence</span><span class="special">,</span> <span class="identifier">Pred</span><span class="special">&gt;::</span><span class="identifier">type</span>
 120 </pre>
 121 <p>
 122             <span class="bold"><strong>Return type</strong></span>: <code class="computeroutput"><span class="keyword">int</span></code>.
 123           </p>
 124 <p>
 125             <span class="bold"><strong>Semantics</strong></span>: Returns the return type of
 126             <a class="link" href="../functions/count_if.html" title="count_if"><code class="computeroutput"><span class="identifier">count_if</span></code></a>. The return type is
 127             always <code class="computeroutput"><span class="keyword">int</span></code>.
 128           </p>
 129 <h6>
 130 <a name="fusion.algorithm.query.metafunctions.count_if.h3"></a>
 131             <span><a name="fusion.algorithm.query.metafunctions.count_if.complexity"></a></span><a class="link" href="count_if.html#fusion.algorithm.query.metafunctions.count_if.complexity">Complexity</a>
 132           </h6>
 133 <p>
 134             Constant.
 135           </p>
 136 <h6>
 137 <a name="fusion.algorithm.query.metafunctions.count_if.h4"></a>
 138             <span><a name="fusion.algorithm.query.metafunctions.count_if.header"></a></span><a class="link" href="count_if.html#fusion.algorithm.query.metafunctions.count_if.header">Header</a>
 139           </h6>
 140 <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fusion</span><span class="special">/</span><span class="identifier">algorithm</span><span class="special">/</span><span class="identifier">query</span><span class="special">/</span><span class="identifier">count_if</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
 141 <span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fusion</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">count_if</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
 142 </pre>
 143 </div>
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