1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Function combine</title> 5<link rel="stylesheet" href="../../../../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../../index.html" title="Chapter 1. Range 2.0"> 8<link rel="up" href="../utilities.html" title="Utilities"> 9<link rel="prev" href="sub_range.html" title="Class sub_range"> 10<link rel="next" href="join.html" title="Function join"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="sub_range.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../utilities.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="join.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h4 class="title"> 27<a name="range.reference.utilities.combine"></a><a class="link" href="combine.html" title="Function combine">Function combine</a> 28</h4></div></div></div> 29<p> 30 The <code class="computeroutput"><span class="identifier">combine</span></code> function is 31 used to make one range from multiple ranges. The <code class="computeroutput"><span class="identifier">combine</span></code> 32 function returns a <code class="computeroutput"><span class="identifier">combined_range</span></code> 33 which is an <code class="computeroutput"><span class="identifier">iterator_range</span></code> 34 of a <code class="computeroutput"><span class="identifier">zip_iterator</span></code> from 35 the Boost.Iterator library. 36 </p> 37<h5> 38<a name="range.reference.utilities.combine.h0"></a> 39 <span class="phrase"><a name="range.reference.utilities.combine.synopsis"></a></span><a class="link" href="combine.html#range.reference.utilities.combine.synopsis">Synopsis</a> 40 </h5> 41<p> 42</p> 43<pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">boost</span> 44<span class="special">{</span> 45 <span class="keyword">namespace</span> <span class="identifier">range</span> 46 <span class="special">{</span> 47 48<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">IterTuple</span><span class="special">></span> 49<span class="keyword">class</span> <span class="identifier">combined_range</span> 50 <span class="special">:</span> <span class="keyword">public</span> <span class="identifier">iterator_range</span><span class="special"><</span><span class="identifier">zip_iterator</span><span class="special"><</span><span class="identifier">IterTuple</span><span class="special">></span> <span class="special">></span> 51<span class="special">{</span> 52<span class="keyword">public</span><span class="special">:</span> 53 <span class="identifier">combined_range</span><span class="special">(</span><span class="identifier">IterTuple</span> <span class="identifier">first</span><span class="special">,</span> <span class="identifier">IterTuple</span> <span class="identifier">last</span><span class="special">);</span> 54<span class="special">};</span> 55 56<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span><span class="special">...</span> <span class="identifier">Ranges</span><span class="special">></span> 57<span class="keyword">auto</span> <span class="identifier">combine</span><span class="special">(</span><span class="identifier">Ranges</span><span class="special">&&...</span> <span class="identifier">rngs</span><span class="special">)</span> <span class="special">-></span> 58 <span class="identifier">combined_range</span><span class="special"><</span><span class="keyword">decltype</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">make_tuple</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">begin</span><span class="special">(</span><span class="identifier">rngs</span><span class="special">)...))></span> 59 60 <span class="special">}</span> <span class="comment">// namespace range</span> 61<span class="special">}</span> <span class="comment">// namespace boost</span> 62</pre> 63<p> 64 </p> 65<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 66<li class="listitem"> 67 <span class="bold"><strong>Precondition:</strong></span> For each type <code class="computeroutput"><span class="identifier">r</span></code> in <code class="computeroutput"><span class="identifier">Ranges</span></code>, 68 <code class="computeroutput"><span class="identifier">r</span></code> is a model of <a class="link" href="../../concepts/single_pass_range.html" title="Single Pass Range">Single Pass Range</a> 69 or better. 70 </li> 71<li class="listitem"> 72 <span class="bold"><strong>Return Type:</strong></span> <code class="computeroutput"><span class="identifier">combined_range</span><span class="special"><</span><span class="identifier">tuple</span><span class="special"><</span><span class="keyword">typename</span> 73 <span class="identifier">range_iterator</span><span class="special"><</span><span class="identifier">Ranges</span><span class="special">>::</span><span class="identifier">type</span><span class="special">...></span> 74 <span class="special">></span></code> 75 </li> 76<li class="listitem"> 77 <span class="bold"><strong>Returned Range Category:</strong></span> The minimum 78 of the range category of every range <code class="computeroutput"><span class="identifier">r</span></code> 79 in <code class="computeroutput"><span class="identifier">Ranges</span></code>. 80 </li> 81</ul></div> 82<h5> 83<a name="range.reference.utilities.combine.h1"></a> 84 <span class="phrase"><a name="range.reference.utilities.combine.example"></a></span><a class="link" href="combine.html#range.reference.utilities.combine.example">Example</a> 85 </h5> 86<p> 87</p> 88<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">range</span><span class="special">/</span><span class="identifier">combine</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 89<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">foreach</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 90<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">iostream</span><span class="special">></span> 91<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">vector</span><span class="special">></span> 92<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">list</span><span class="special">></span> 93 94<span class="keyword">int</span> <span class="identifier">main</span><span class="special">(</span><span class="keyword">int</span><span class="special">,</span> <span class="keyword">const</span> <span class="keyword">char</span><span class="special">*[])</span> 95<span class="special">{</span> 96 <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="keyword">int</span><span class="special">></span> <span class="identifier">v</span><span class="special">;</span> 97 <span class="identifier">std</span><span class="special">::</span><span class="identifier">list</span><span class="special"><</span><span class="keyword">char</span><span class="special">></span> <span class="identifier">l</span><span class="special">;</span> 98 <span class="keyword">for</span> <span class="special">(</span><span class="keyword">int</span> <span class="identifier">i</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span> <span class="identifier">i</span> <span class="special"><</span> <span class="number">5</span><span class="special">;</span> <span class="special">++</span><span class="identifier">i</span><span class="special">)</span> 99 <span class="special">{</span> 100 <span class="identifier">v</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">i</span><span class="special">);</span> 101 <span class="identifier">l</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="keyword">static_cast</span><span class="special"><</span><span class="keyword">char</span><span class="special">>(</span><span class="identifier">i</span><span class="special">)</span> <span class="special">+</span> <span class="char">'a'</span><span class="special">);</span> 102 <span class="special">}</span> 103 104 <span class="keyword">int</span> <span class="identifier">ti</span><span class="special">;</span> 105 <span class="keyword">char</span> <span class="identifier">tc</span><span class="special">;</span> 106 <span class="identifier">BOOST_FOREACH</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">tie</span><span class="special">(</span><span class="identifier">ti</span><span class="special">,</span> <span class="identifier">tc</span><span class="special">),</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">combine</span><span class="special">(</span><span class="identifier">v</span><span class="special">,</span> <span class="identifier">l</span><span class="special">))</span> 107 <span class="special">{</span> 108 <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="char">'('</span> <span class="special"><<</span> <span class="identifier">ti</span> <span class="special"><<</span> <span class="char">','</span> <span class="special"><<</span> <span class="identifier">tc</span> <span class="special"><<</span> <span class="char">')'</span> <span class="special"><<</span> <span class="char">'\n'</span><span class="special">;</span> 109 <span class="special">}</span> 110 111 <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span> 112<span class="special">}</span> 113</pre> 114<p> 115 </p> 116<p> 117 This produces the output: 118</p> 119<pre class="programlisting"><span class="special">(</span><span class="number">0</span><span class="special">,</span><span class="identifier">a</span><span class="special">)</span> 120<span class="special">(</span><span class="number">1</span><span class="special">,</span><span class="identifier">b</span><span class="special">)</span> 121<span class="special">(</span><span class="number">2</span><span class="special">,</span><span class="identifier">c</span><span class="special">)</span> 122<span class="special">(</span><span class="number">3</span><span class="special">,</span><span class="identifier">d</span><span class="special">)</span> 123<span class="special">(</span><span class="number">4</span><span class="special">,</span><span class="identifier">e</span><span class="special">)</span> 124</pre> 125<p> 126 </p> 127</div> 128<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 129<td align="left"></td> 130<td align="right"><div class="copyright-footer">Copyright © 2003-2010 Thorsten Ottosen, 131 Neil Groves<p> 132 Distributed under the Boost Software License, Version 1.0. (See accompanying 133 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>) 134 </p> 135</div></td> 136</tr></table> 137<hr> 138<div class="spirit-nav"> 139<a accesskey="p" href="sub_range.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../utilities.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="join.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 140</div> 141</body> 142</html> 143
