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  25 <div class="section">
  26 <div class="titlepage"><div><div><h5 class="title">
  27 <a name="fusion.algorithm.iteration.functions.reverse_iter_fold"></a><a class="link" href="reverse_iter_fold.html" title="reverse_iter_fold">reverse_iter_fold</a>
  28 </h5></div></div></div>
  29 <h6>
  30 <a name="fusion.algorithm.iteration.functions.reverse_iter_fold.h0"></a>
  31             <span class="phrase"><a name="fusion.algorithm.iteration.functions.reverse_iter_fold.description"></a></span><a class="link" href="reverse_iter_fold.html#fusion.algorithm.iteration.functions.reverse_iter_fold.description">Description</a>
  32           </h6>
  33 <p>
  34             For a sequence <code class="computeroutput"><span class="identifier">seq</span></code>, initial
  35             state <code class="computeroutput"><span class="identifier">initial_state</span></code>,
  36             and binary function object or function pointer <code class="computeroutput"><span class="identifier">f</span></code>,
  37             <code class="literal">reverse_iter_fold</code> returns the result of the repeated
  38             application of binary <code class="computeroutput"><span class="identifier">f</span></code>
  39             to the result of the previous <code class="computeroutput"><span class="identifier">f</span></code>
  40             invocation (<code class="computeroutput"><span class="identifier">inital_state</span></code>
  41             if it is the first call) and iterators on each element of <code class="computeroutput"><span class="identifier">seq</span></code>.
  42           </p>
  43 <h6>
  44 <a name="fusion.algorithm.iteration.functions.reverse_iter_fold.h1"></a>
  45             <span class="phrase"><a name="fusion.algorithm.iteration.functions.reverse_iter_fold.synopsis"></a></span><a class="link" href="reverse_iter_fold.html#fusion.algorithm.iteration.functions.reverse_iter_fold.synopsis">Synopsis</a>
  46           </h6>
  47 <pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span>
  48     <span class="keyword">typename</span> <span class="identifier">Sequence</span><span class="special">,</span>
  49     <span class="keyword">typename</span> <span class="identifier">State</span><span class="special">,</span>
  50     <span class="keyword">typename</span> <span class="identifier">F</span>
  51     <span class="special">&gt;</span>
  52 <span class="keyword">typename</span> <a class="link" href="../metafunctions/reverse_iter_fold.html" title="reverse_iter_fold"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">reverse_iter_fold</span></code></a><span class="special">&lt;</span><span class="identifier">Sequence</span><span class="special">,</span> <span class="identifier">State</span> <span class="keyword">const</span><span class="special">,</span> <span class="identifier">F</span><span class="special">&gt;::</span><span class="identifier">type</span> reverse_iter_fold<span class="special">(</span>
  53     <span class="identifier">Sequence</span><span class="special">&amp;</span> <span class="identifier">seq</span><span class="special">,</span> <span class="identifier">State</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">initial_state</span><span class="special">,</span> <span class="identifier">F</span> <span class="identifier">f</span><span class="special">);</span>
  54
  55 <span class="keyword">template</span><span class="special">&lt;</span>
  56     <span class="keyword">typename</span> <span class="identifier">Sequence</span><span class="special">,</span>
  57     <span class="keyword">typename</span> <span class="identifier">State</span><span class="special">,</span>
  58     <span class="keyword">typename</span> <span class="identifier">F</span>
  59     <span class="special">&gt;</span>
  60 <span class="keyword">typename</span> <a class="link" href="../metafunctions/reverse_iter_fold.html" title="reverse_iter_fold"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">reverse_iter_fold</span></code></a><span class="special">&lt;</span><span class="identifier">Sequence</span> <span class="keyword">const</span><span class="special">,</span> <span class="identifier">State</span> <span class="keyword">const</span><span class="special">,</span> <span class="identifier">F</span><span class="special">&gt;::</span><span class="identifier">type</span> reverse_iter_fold<span class="special">(</span>
  61     <span class="identifier">Sequence</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">seq</span><span class="special">,</span> <span class="identifier">State</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">initial_state</span><span class="special">,</span> <span class="identifier">F</span> <span class="identifier">f</span><span class="special">);</span>
  62 </pre>
  63 <div class="table">
  64 <a name="fusion.algorithm.iteration.functions.reverse_iter_fold.t0"></a><p class="title"><b>Table&#160;1.41.&#160;Parameters</b></p>
  65 <div class="table-contents"><table class="table" summary="Parameters">
  66 <colgroup>
  67 <col>
  68 <col>
  69 <col>
  70 </colgroup>
  71 <thead><tr>
  72 <th>
  73                     <p>
  74                       Parameter
  75                     </p>
  76                   </th>
  77 <th>
  78                     <p>
  79                       Requirement
  80                     </p>
  81                   </th>
  82 <th>
  83                     <p>
  84                       Description
  85                     </p>
  86                   </th>
  87 </tr></thead>
  88 <tbody>
  89 <tr>
  90 <td>
  91                     <p>
  92                       <code class="computeroutput"><span class="identifier">seq</span></code>
  93                     </p>
  94                   </td>
  95 <td>
  96                     <p>
  97                       A model of <a class="link" href="../../../sequence/concepts/bidirectional_sequence.html" title="Bidirectional Sequence">Bidirectional
  98                       Sequence</a>
  99                     </p>
 100                   </td>
 101 <td>
 102                     <p>
 103                       Operation's argument
 104                     </p>
 105                   </td>
 106 </tr>
 107 <tr>
 108 <td>
 109                     <p>
 110                       <code class="computeroutput"><span class="identifier">initial_state</span></code>
 111                     </p>
 112                   </td>
 113 <td>
 114                     <p>
 115                       Any type
 116                     </p>
 117                   </td>
 118 <td>
 119                     <p>
 120                       Initial state
 121                     </p>
 122                   </td>
 123 </tr>
 124 <tr>
 125 <td>
 126                     <p>
 127                       <code class="computeroutput"><span class="identifier">f</span></code>
 128                     </p>
 129                   </td>
 130 <td>
 131                     <p>
 132                       <code class="computeroutput"><span class="identifier">f</span><span class="special">(</span><span class="identifier">s</span><span class="special">,</span>it<span class="special">)</span></code> with return type <code class="computeroutput"><a href="http://www.boost.org/libs/utility/utility.htm#result_of" target="_top"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">result_of</span></code></a><span class="special">&lt;</span><span class="identifier">F</span><span class="special">(</span><span class="identifier">S</span><span class="special">,</span>It<span class="special">)&gt;::</span><span class="identifier">type</span></code> for current state <code class="computeroutput"><span class="identifier">s</span></code> of type <code class="computeroutput"><span class="identifier">S</span></code>,
 133                       and for each iterator <code class="computeroutput"><span class="identifier">it</span></code>
 134                       of type <code class="computeroutput"><span class="identifier">It</span></code>
 135                       on an element of <code class="computeroutput"><span class="identifier">seq</span></code>
 136                     </p>
 137                   </td>
 138 <td>
 139                     <p>
 140                       Operation's argument
 141                     </p>
 142                   </td>
 143 </tr>
 144 </tbody>
 145 </table></div>
 146 </div>
 147 <br class="table-break"><h6>
 148 <a name="fusion.algorithm.iteration.functions.reverse_iter_fold.h2"></a>
 149             <span class="phrase"><a name="fusion.algorithm.iteration.functions.reverse_iter_fold.expression_semantics"></a></span><a class="link" href="reverse_iter_fold.html#fusion.algorithm.iteration.functions.reverse_iter_fold.expression_semantics">Expression
 150             Semantics</a>
 151           </h6>
 152 <pre class="programlisting">reverse_iter_fold<span class="special">(</span><span class="identifier">seq</span><span class="special">,</span> <span class="identifier">initial_state</span><span class="special">,</span> <span class="identifier">f</span><span class="special">);</span>
 153 </pre>
 154 <p>
 155             <span class="bold"><strong>Return type</strong></span>: Any type
 156           </p>
 157 <p>
 158             <span class="bold"><strong>Semantics</strong></span>: Equivalent to <code class="literal">f(...
 159             f(f(initial_state,itN),itN-1) ...it1)</code> where <code class="literal">it1 ...itN</code>
 160             are consecutive iterators on the elements of <code class="computeroutput"><span class="identifier">seq</span></code>.
 161           </p>
 162 <h6>
 163 <a name="fusion.algorithm.iteration.functions.reverse_iter_fold.h3"></a>
 164             <span class="phrase"><a name="fusion.algorithm.iteration.functions.reverse_iter_fold.complexity"></a></span><a class="link" href="reverse_iter_fold.html#fusion.algorithm.iteration.functions.reverse_iter_fold.complexity">Complexity</a>
 165           </h6>
 166 <p>
 167             Linear, exactly <code class="computeroutput"><a class="link" href="../../../sequence/intrinsic/metafunctions/size.html" title="size"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">size</span></code></a><span class="special">&lt;</span><span class="identifier">Sequence</span><span class="special">&gt;::</span><span class="identifier">value</span></code> applications of <code class="computeroutput"><span class="identifier">f</span></code>.
 168           </p>
 169 <h6>
 170 <a name="fusion.algorithm.iteration.functions.reverse_iter_fold.h4"></a>
 171             <span class="phrase"><a name="fusion.algorithm.iteration.functions.reverse_iter_fold.header"></a></span><a class="link" href="reverse_iter_fold.html#fusion.algorithm.iteration.functions.reverse_iter_fold.header">Header</a>
 172           </h6>
 173 <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">iteration</span><span class="special">/</span>reverse_iter_fold<span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
 174 <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>reverse_iter_fold<span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
 175 </pre>
 176 <h6>
 177 <a name="fusion.algorithm.iteration.functions.reverse_iter_fold.h5"></a>
 178             <span class="phrase"><a name="fusion.algorithm.iteration.functions.reverse_iter_fold.example"></a></span><a class="link" href="reverse_iter_fold.html#fusion.algorithm.iteration.functions.reverse_iter_fold.example">Example</a>
 179           </h6>
 180 <pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">make_string</span>
 181 <span class="special">{</span>
 182     <span class="keyword">typedef</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="identifier">result_type</span><span class="special">;</span>
 183
 184     <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">&gt;</span>
 185     <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="keyword">operator</span><span class="special">()(</span><span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">&amp;</span> <span class="identifier">str</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">T</span><span class="special">&amp;</span> <span class="identifier">t</span><span class="special">)</span> <span class="keyword">const</span>
 186     <span class="special">{</span>
 187         <span class="keyword">return</span> <span class="identifier">str</span> <span class="special">+</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">lexical_cast</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">&gt;(</span><a class="link" href="../../../iterator/functions/deref.html" title="deref"><code class="computeroutput"><span class="identifier">deref</span></code></a>(t)<span class="special">);</span>
 188     <span class="special">}</span>
 189 <span class="special">};</span>
 190 <span class="special">...</span>
 191 <span class="keyword">const</span> <a class="link" href="../../../container/vector.html" title="vector"><code class="computeroutput"><span class="identifier">vector</span></code></a><span class="special">&lt;</span><span class="keyword">int</span><span class="special">,</span><span class="keyword">int</span><span class="special">&gt;</span> <span class="identifier">vec</span><span class="special">(</span><span class="number">1</span><span class="special">,</span><span class="number">2</span><span class="special">);</span>
 192 <span class="identifier">assert</span><span class="special">(</span>reverse_iter_fold<span class="special">(</span><span class="identifier">vec</span><span class="special">,</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">(</span><span class="string">""</span><span class="special">),</span> <span class="identifier">make_string</span><span class="special">())</span> <span class="special">==</span> "21"<span class="special">);</span>
 193 </pre>
 194 </div>
 195 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 196 <td align="left"></td>
 197 <td align="right"><div class="copyright-footer">Copyright &#169; 2001-2006, 2011, 2012 Joel de Guzman,
 198       Dan Marsden, Tobias Schwinger<p>
 199         Distributed under the Boost Software License, Version 1.0. (See accompanying
 200         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
 201       </p>
 202 </div></td>
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