1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>nth_element</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="../mutating.html" title="Mutating algorithms"> 9<link rel="prev" href="merge.html" title="merge"> 10<link rel="next" href="partial_sort.html" title="partial_sort"> 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="merge.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../mutating.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="partial_sort.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h5 class="title"> 27<a name="range.reference.algorithms.mutating.nth_element"></a><a class="link" href="nth_element.html" title="nth_element">nth_element</a> 28</h5></div></div></div> 29<h6> 30<a name="range.reference.algorithms.mutating.nth_element.h0"></a> 31 <span class="phrase"><a name="range.reference.algorithms.mutating.nth_element.prototype"></a></span><a class="link" href="nth_element.html#range.reference.algorithms.mutating.nth_element.prototype">Prototype</a> 32 </h6> 33<p> 34</p> 35<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">RandomAccessRange</span><span class="special">></span> 36<span class="identifier">RandomAccessRange</span><span class="special">&</span> <span class="identifier">nth_element</span><span class="special">(</span> 37 <span class="identifier">RandomAccessRange</span><span class="special">&</span> <span class="identifier">rng</span><span class="special">,</span> 38 <span class="keyword">typename</span> <span class="identifier">range_iterator</span><span class="special"><</span><span class="identifier">RandomAccessRange</span><span class="special">>::</span><span class="identifier">type</span> <span class="identifier">nth</span><span class="special">);</span> 39 40<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">RandomAccessRange</span><span class="special">></span> 41<span class="keyword">const</span> <span class="identifier">RandomAccessRange</span><span class="special">&</span> <span class="identifier">nth_element</span><span class="special">(</span> 42 <span class="keyword">const</span> <span class="identifier">RandomAccessRange</span><span class="special">&</span> <span class="identifier">rng</span><span class="special">,</span> 43 <span class="keyword">typename</span> <span class="identifier">range_iterator</span><span class="special"><</span><span class="keyword">const</span> <span class="identifier">RandomAccessRange</span><span class="special">>::</span><span class="identifier">type</span> <span class="identifier">nth</span><span class="special">);</span> 44 45<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">RandomAccessRange</span><span class="special">></span> 46<span class="identifier">RandomAccessRange</span><span class="special">&</span> <span class="identifier">nth_element</span><span class="special">(</span> 47 <span class="identifier">RandomAccessRange</span><span class="special">&</span> <span class="identifier">rng</span><span class="special">,</span> 48 <span class="keyword">typename</span> <span class="identifier">range_iterator</span><span class="special"><</span><span class="identifier">RandomAccessRange</span><span class="special">>::</span><span class="identifier">type</span> <span class="identifier">nth</span><span class="special">,</span> 49 <span class="identifier">BinaryPredicate</span> <span class="identifier">sort_pred</span><span class="special">);</span> 50 51<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">RandomAccessRange</span><span class="special">></span> 52<span class="keyword">const</span> <span class="identifier">RandomAccessRange</span><span class="special">&</span> <span class="identifier">nth_element</span><span class="special">(</span> 53 <span class="keyword">const</span> <span class="identifier">RandomAccessRange</span><span class="special">&</span> <span class="identifier">rng</span><span class="special">,</span> 54 <span class="keyword">typename</span> <span class="identifier">range_iterator</span><span class="special"><</span><span class="keyword">const</span> <span class="identifier">RandomAccessRange</span><span class="special">>::</span><span class="identifier">type</span> <span class="identifier">nth</span><span class="special">,</span> 55 <span class="identifier">BinaryPredicate</span> <span class="identifier">sort_pred</span><span class="special">);</span> 56</pre> 57<p> 58 </p> 59<h6> 60<a name="range.reference.algorithms.mutating.nth_element.h1"></a> 61 <span class="phrase"><a name="range.reference.algorithms.mutating.nth_element.description"></a></span><a class="link" href="nth_element.html#range.reference.algorithms.mutating.nth_element.description">Description</a> 62 </h6> 63<p> 64 <code class="computeroutput"><span class="identifier">nth_element</span></code> partially 65 orders a range of elements. <code class="computeroutput"><span class="identifier">nth_element</span></code> 66 arranges the range <code class="computeroutput"><span class="identifier">rng</span></code> 67 such that the element corresponding with the iterator <code class="computeroutput"><span class="identifier">nth</span></code> 68 is the same as the element that would be in that position if <code class="computeroutput"><span class="identifier">rng</span></code> has been sorted. 69 </p> 70<h6> 71<a name="range.reference.algorithms.mutating.nth_element.h2"></a> 72 <span class="phrase"><a name="range.reference.algorithms.mutating.nth_element.definition"></a></span><a class="link" href="nth_element.html#range.reference.algorithms.mutating.nth_element.definition">Definition</a> 73 </h6> 74<p> 75 Defined in the header file <code class="computeroutput"><span class="identifier">boost</span><span class="special">/</span><span class="identifier">range</span><span class="special">/</span><span class="identifier">algorithm</span><span class="special">/</span><span class="identifier">nth_element</span><span class="special">.</span><span class="identifier">hpp</span></code> 76 </p> 77<h6> 78<a name="range.reference.algorithms.mutating.nth_element.h3"></a> 79 <span class="phrase"><a name="range.reference.algorithms.mutating.nth_element.requirements"></a></span><a class="link" href="nth_element.html#range.reference.algorithms.mutating.nth_element.requirements">Requirements</a> 80 </h6> 81<p> 82 <span class="bold"><strong>For the non-predicate version:</strong></span> 83 </p> 84<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 85<li class="listitem"> 86 <code class="computeroutput"><span class="identifier">RandomAccessRange</span></code> 87 is a model of the <a class="link" href="../../../concepts/random_access_range.html" title="Random Access Range">Random 88 Access Range</a> Concept. 89 </li> 90<li class="listitem"> 91 <code class="computeroutput"><span class="identifier">RandomAccessRange</span></code> 92 is mutable. 93 </li> 94<li class="listitem"> 95 <code class="computeroutput"><span class="identifier">RandomAccessRange</span></code>'s 96 value type is a model of the <code class="computeroutput"><span class="identifier">LessThanComparableConcept</span></code>. 97 </li> 98<li class="listitem"> 99 The ordering relation on <code class="computeroutput"><span class="identifier">RandomAccessRange</span></code>'s 100 value type is a <span class="bold"><strong><span class="emphasis"><em>strict weak ordering</em></span></strong></span>, 101 as defined in the <code class="computeroutput"><span class="identifier">LessThanComparableConcept</span></code> 102 requirements. 103 </li> 104</ul></div> 105<p> 106 <span class="bold"><strong>For the predicate version:</strong></span> 107 </p> 108<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 109<li class="listitem"> 110 <code class="computeroutput"><span class="identifier">RandomAccessRange</span></code> 111 is a model of the <a class="link" href="../../../concepts/random_access_range.html" title="Random Access Range">Random 112 Access Range</a> Concept. 113 </li> 114<li class="listitem"> 115 <code class="computeroutput"><span class="identifier">RandomAccessRange</span></code> 116 is mutable. 117 </li> 118<li class="listitem"> 119 <code class="computeroutput"><span class="identifier">BinaryPredicate</span></code> is 120 a model of the <code class="computeroutput"><span class="identifier">StrictWeakOrderingConcept</span></code>. 121 </li> 122<li class="listitem"> 123 <code class="computeroutput"><span class="identifier">RandomAccessRange</span></code>'s 124 value type is convertible to both of <code class="computeroutput"><span class="identifier">BinaryPredicate</span></code>'s 125 argument types. 126 </li> 127</ul></div> 128<h6> 129<a name="range.reference.algorithms.mutating.nth_element.h4"></a> 130 <span class="phrase"><a name="range.reference.algorithms.mutating.nth_element.complexity"></a></span><a class="link" href="nth_element.html#range.reference.algorithms.mutating.nth_element.complexity">Complexity</a> 131 </h6> 132<p> 133 On average, linear in <code class="computeroutput"><span class="identifier">distance</span><span class="special">(</span><span class="identifier">rng</span><span class="special">)</span></code>. 134 </p> 135</div> 136<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 137<td align="left"></td> 138<td align="right"><div class="copyright-footer">Copyright © 2003-2010 Thorsten Ottosen, 139 Neil Groves<p> 140 Distributed under the Boost Software License, Version 1.0. (See accompanying 141 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>) 142 </p> 143</div></td> 144</tr></table> 145<hr> 146<div class="spirit-nav"> 147<a accesskey="p" href="merge.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../mutating.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="partial_sort.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 148</div> 149</body> 150</html> 151
