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60 lines
2.6 KiB
HTML
60 lines
2.6 KiB
HTML
<!doctype html public "-//ietf//dtd html//en">
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<html><head><title>boost::mpl::Reference/count</title>
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<link rel="stylesheet" href="../mpl_wiki.css">
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</head><body bgcolor="white">
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<h1><a href="../Table_of_Content.html"><img src="../mpl_logo.jpg" alt="[Home]" border=0 align="right"></a>count</h1><h3>Synopsis</h3>
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<p>
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<pre>
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template<
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typename Sequence
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, typename T
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>
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struct count
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{
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typedef <em>unspecified</em> type;
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};
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</pre>
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<p>
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<h3>Description</h3>
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<p>
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Returns the number of elements in a <code>Sequence</code> that are identical to <code>T</code>.
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<p>
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<h3>Definition</h3>
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<p>
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<pre>
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#include "<a href="../../../../../\boost/mpl/count_if.hpp">boost/mpl/count_if.hpp</a>"
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</pre>
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<p>
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<h3>Parameters</h3>
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<table border="1">
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<tr><th> Parameter </th><th> Requirement </th><th> Description </th></tr>
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<tr><td><code>Sequence</code></td><td>A model of <a href="../Forward_Sequence.html">Forward Sequence</a></td><td>A sequence to be examined. </td></tr>
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<tr><td><code>T</code></td><td>A type</td><td>The type to be searched for. </td></tr>
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</table>
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<p>
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<h3>Expression semantics</h3>
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<p>
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<table border="1">
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<tr><th> Expression </th><th> Expression type </th><th> Precondition </th><th> Semantics </th><th> Postcondition </th></tr>
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<tr><td><code>typedef count<Sequence,T>::type n;</code></td><td>A model of <a href="../Integral_Constant.html">Integral Constant</a></td><td></td><td>Equivalent to <code>typedef <a href="../Reference/count_if.html">count_if</a>< Sequence,is_same<_,T> >::type n;</code></td><td></td></tr>
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</table>
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<p>
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<p>
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<h3>Complexity</h3>
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<p>
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Linear. Exactly <code><a href="../Reference/size.html">size</a><Sequence>::value</code> comparisons for identity.
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<p>
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<h3>Example</h3>
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<p>
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<pre>
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typedef <a href="../Reference/list.html">list</a><int,char,long,short,char,short,double,long> types;
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typedef find<types, short>::type iter;
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BOOST_STATIC_ASSERT((is_same<iter::type,short>::type::value));
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BOOST_STATIC_ASSERT((<a href="../Reference/distance.html">distance</a>< begin<types>::type,iter >::type::value == 3));
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</pre>
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<p>
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<h3>See also</h3>
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<p>
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<a href="../Algorithms.html">Algorithms</a>, <code><a href="../Reference/count_if.html">count_if</a></code>, <code><a href="../Reference/find.html">find</a></code>, <code><a href="../Reference/find_if.html">find_if</a></code>, <code><a href="../Reference/contains.html">contains</a></code>
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<p><hr>
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<a href="../Table_of_Content.html">Table of Content</a> | <a href="../Reference.html">Reference</a><br>Last edited July 17, 2002 4:32 am</body></html> |