forked from boostorg/range
118 lines
3.7 KiB
HTML
118 lines
3.7 KiB
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
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<title>Boost.Range Range Adaptors </title>
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<link rel="stylesheet" href="../style.css" type="text/css">
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</head>
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<body>
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<table border="0" >
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<tr>
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<td ><img src="../../../boost.png" border="0" /></td>
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<td ><h1 align="center">Boost.Range </h1></td>
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</tr>
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</table>
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<h2> Range Adaptors </h2>
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<hr />
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<a name="indexed"></a>
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<h4><code>indexed</code></h4>
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<blockquote>
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<pre>rng | boost::adaptors::indexed</pre>
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<pre>boost::make_indexed_range( rng )</pre>
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</blockquote>
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<ul>
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<li>
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<b>Returns:</b>
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A range adapted to return both the element and the associated
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index.
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The returned range consists of iterators that have in addition
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to the usual iterator member functions an
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<code>index()</code> member function that returns the appropriate
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index for the element in the sequence corresponding with the
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iterator.
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</li>
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<li>
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<b>Range Category:</b>
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SinglePassRange
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</li>
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</ul>
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<hr />
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<h3>Example</h3>
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<pre>
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<span class="keyword">#include</span> <boost/range/adaptor/indexed.hpp>
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<span class="keyword">#include</span> <boost/range/algorithm/copy.hpp>
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<span class="keyword">#include</span> <boost/assign.hpp>
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<span class="keyword">#include</span> <algorithm>
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<span class="keyword">#include</span> <iostream>
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<span class="keyword">#include</span> <vector>
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<span class="keyword">template</span><<span class="keyword">class</span> Iterator>
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void display_element_and_index(Iterator first, Iterator last)
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{
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<span class="keyword">for</span> (Iterator it = first; it != last; ++it)
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{
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std::cout << "Element = " << *it
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<< " Index = " << it.index() << std::endl;
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}
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}
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<span class="keyword">template</span><<span class="keyword">class</span> SinglePassRange>
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void display_element_and_index(<span class="keyword">const</span> SinglePassRange& rng)
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{
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display_element_and_index(boost::begin(rng), boost::end(rng));
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}
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<span class="keyword">int</span> main(<span class="keyword">int</span> argc, <span class="keyword">const char</span>* argv[])
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{
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<span class="keyword">using namespace</span> boost::assign;
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<span class="keyword">using namespace</span> boost::adaptors;
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std::vector<<span class="keyword">int</span>> input;
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input += 10,20,30,40,50,60,70,80,90;
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display_element_and_index( input | indexed(0) );
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<span class="keyword">return</span> 0;
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}
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</pre>
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<p>
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This produces the output: <br />
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<code>
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Element = 10 Index = 0 <br />
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Element = 20 Index = 1 <br />
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Element = 30 Index = 2 <br />
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Element = 40 Index = 3 <br />
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Element = 50 Index = 4 <br />
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Element = 60 Index = 5 <br />
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Element = 70 Index = 6 <br />
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Element = 80 Index = 7 <br />
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Element = 90 Index = 8 <br />
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</code>
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</p>
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<hr />
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<p>
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(C) Copyright Neil Groves 2009
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(C) Copyright Thorsten Ottosen 2003-2004
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</p>
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<br />
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<br />
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<br />
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</body>
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</html>
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