1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>lower_bound</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="../non_mutating.html" title="Non-mutating algorithms"> 9<link rel="prev" href="lexicographical_compare.html" title="lexicographical_compare"> 10<link rel="next" href="max_element.html" title="max_element"> 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="lexicographical_compare.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../non_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="max_element.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.non_mutating.lower_bound"></a><a class="link" href="lower_bound.html" title="lower_bound">lower_bound</a> 28</h5></div></div></div> 29<h6> 30<a name="range.reference.algorithms.non_mutating.lower_bound.h0"></a> 31 <span class="phrase"><a name="range.reference.algorithms.non_mutating.lower_bound.prototype"></a></span><a class="link" href="lower_bound.html#range.reference.algorithms.non_mutating.lower_bound.prototype">Prototype</a> 32 </h6> 33<p> 34</p> 35<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> 36 <span class="keyword">class</span> <span class="identifier">ForwardRange</span><span class="special">,</span> 37 <span class="keyword">class</span> <span class="identifier">Value</span> 38 <span class="special">></span> 39<span class="keyword">typename</span> <span class="identifier">range_iterator</span><span class="special"><</span><span class="identifier">ForwardRange</span><span class="special">>::</span><span class="identifier">type</span> 40<span class="identifier">lower_bound</span><span class="special">(</span><span class="identifier">ForwardRange</span><span class="special">&</span> <span class="identifier">rng</span><span class="special">,</span> <span class="identifier">Value</span> <span class="identifier">val</span><span class="special">);</span> 41 42<span class="keyword">template</span><span class="special"><</span> 43 <span class="identifier">range_return_value</span> <span class="identifier">re</span><span class="special">,</span> 44 <span class="keyword">class</span> <span class="identifier">ForwardRange</span><span class="special">,</span> 45 <span class="keyword">class</span> <span class="identifier">Value</span> 46 <span class="special">></span> 47<span class="keyword">typename</span> <span class="identifier">range_return</span><span class="special"><</span><span class="identifier">ForwardRange</span><span class="special">,</span> <span class="identifier">re</span><span class="special">>::</span><span class="identifier">type</span> 48<span class="identifier">lower_bound</span><span class="special">(</span><span class="identifier">ForwardRange</span><span class="special">&</span> <span class="identifier">rng</span><span class="special">,</span> <span class="identifier">Value</span> <span class="identifier">val</span><span class="special">);</span> 49 50<span class="keyword">template</span><span class="special"><</span> 51 <span class="keyword">class</span> <span class="identifier">ForwardRange</span><span class="special">,</span> 52 <span class="keyword">class</span> <span class="identifier">Value</span><span class="special">,</span> 53 <span class="keyword">class</span> <span class="identifier">SortPredicate</span> 54 <span class="special">></span> 55<span class="keyword">typename</span> <span class="identifier">range_iterator</span><span class="special"><</span><span class="identifier">ForwardRange</span><span class="special">>::</span><span class="identifier">type</span> 56<span class="identifier">lower_bound</span><span class="special">(</span><span class="identifier">ForwardRange</span><span class="special">&</span> <span class="identifier">rng</span><span class="special">,</span> <span class="identifier">Value</span> <span class="identifier">val</span><span class="special">,</span> <span class="identifier">SortPredicate</span> <span class="identifier">pred</span><span class="special">);</span> 57 58<span class="keyword">template</span><span class="special"><</span> 59 <span class="identifier">range_return_value</span> <span class="identifier">re</span><span class="special">,</span> 60 <span class="keyword">class</span> <span class="identifier">ForwardRange</span><span class="special">,</span> 61 <span class="keyword">class</span> <span class="identifier">Value</span><span class="special">,</span> 62 <span class="keyword">class</span> <span class="identifier">SortPredicate</span> 63 <span class="special">></span> 64<span class="keyword">typename</span> <span class="identifier">range_return</span><span class="special"><</span><span class="identifier">ForwardRange</span><span class="special">,</span><span class="identifier">re</span><span class="special">>::</span><span class="identifier">type</span> 65<span class="identifier">lower_bound</span><span class="special">(</span><span class="identifier">ForwardRange</span><span class="special">&</span> <span class="identifier">rng</span><span class="special">,</span> <span class="identifier">Value</span> <span class="identifier">val</span><span class="special">,</span> <span class="identifier">SortPredicate</span> <span class="identifier">pred</span><span class="special">);</span> 66</pre> 67<p> 68 </p> 69<h6> 70<a name="range.reference.algorithms.non_mutating.lower_bound.h1"></a> 71 <span class="phrase"><a name="range.reference.algorithms.non_mutating.lower_bound.description"></a></span><a class="link" href="lower_bound.html#range.reference.algorithms.non_mutating.lower_bound.description">Description</a> 72 </h6> 73<p> 74 The versions of <code class="computeroutput"><span class="identifier">lower_bound</span></code> 75 that return an iterator, returns the first iterator in the range <code class="computeroutput"><span class="identifier">rng</span></code> such that: without predicate - 76 <code class="computeroutput"><span class="special">*</span><span class="identifier">i</span> 77 <span class="special"><</span> <span class="identifier">value</span></code> 78 is <code class="computeroutput"><span class="keyword">false</span></code>, with predicate 79 - <code class="computeroutput"><span class="identifier">pred</span><span class="special">(*</span><span class="identifier">i</span><span class="special">,</span> <span class="identifier">value</span><span class="special">)</span></code> 80 is <code class="computeroutput"><span class="keyword">false</span></code>. 81 </p> 82<p> 83 <code class="computeroutput"><span class="identifier">end</span><span class="special">(</span><span class="identifier">rng</span><span class="special">)</span></code> 84 is returned if no such iterator exists. 85 </p> 86<p> 87 The versions of <code class="computeroutput"><span class="identifier">lower_bound</span></code> 88 that return a <code class="computeroutput"><span class="identifier">range_return</span></code>, 89 defines <code class="computeroutput"><span class="identifier">found</span></code> in the 90 same manner as the returned iterator described above. 91 </p> 92<h6> 93<a name="range.reference.algorithms.non_mutating.lower_bound.h2"></a> 94 <span class="phrase"><a name="range.reference.algorithms.non_mutating.lower_bound.definition"></a></span><a class="link" href="lower_bound.html#range.reference.algorithms.non_mutating.lower_bound.definition">Definition</a> 95 </h6> 96<p> 97 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">lower_bound</span><span class="special">.</span><span class="identifier">hpp</span></code> 98 </p> 99<h6> 100<a name="range.reference.algorithms.non_mutating.lower_bound.h3"></a> 101 <span class="phrase"><a name="range.reference.algorithms.non_mutating.lower_bound.requirements"></a></span><a class="link" href="lower_bound.html#range.reference.algorithms.non_mutating.lower_bound.requirements">Requirements</a> 102 </h6> 103<p> 104 <span class="bold"><strong>For the non-predicate versions:</strong></span> 105 </p> 106<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 107<li class="listitem"> 108 <code class="computeroutput"><span class="identifier">ForwardRange</span></code> is a 109 model of the <a class="link" href="../../../concepts/forward_range.html" title="Forward Range">Forward 110 Range</a> Concept. 111 </li> 112<li class="listitem"> 113 <code class="computeroutput"><span class="identifier">Value</span></code> is a model 114 of the <code class="computeroutput"><span class="identifier">LessThanComparableConcept</span></code>. 115 </li> 116<li class="listitem"> 117 The ordering of objects of type <code class="computeroutput"><span class="identifier">Value</span></code> 118 is a <span class="bold"><strong><span class="emphasis"><em>strict weak ordering</em></span></strong></span>, 119 as defined in the <code class="computeroutput"><span class="identifier">LessThanComparableConcept</span></code> 120 requirements. 121 </li> 122<li class="listitem"> 123 <code class="computeroutput"><span class="identifier">ForwardRange</span></code>'s value 124 type is the same type as <code class="computeroutput"><span class="identifier">Value</span></code>. 125 </li> 126</ul></div> 127<p> 128 <span class="bold"><strong>For the predicate versions:</strong></span> 129 </p> 130<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 131<li class="listitem"> 132 <code class="computeroutput"><span class="identifier">ForwardRange</span></code> is a 133 model of the <a class="link" href="../../../concepts/forward_range.html" title="Forward Range">Forward 134 Range</a> Concept. 135 </li> 136<li class="listitem"> 137 <code class="computeroutput"><span class="identifier">BinaryPredicate</span></code> is 138 a model of the <code class="computeroutput"><span class="identifier">StrictWeakOrderingConcept</span></code>. 139 </li> 140<li class="listitem"> 141 <code class="computeroutput"><span class="identifier">ForwardRange</span></code>'s value 142 type is the same type as <code class="computeroutput"><span class="identifier">Value</span></code>. 143 </li> 144<li class="listitem"> 145 <code class="computeroutput"><span class="identifier">ForwardRange</span></code>'s value 146 type is convertible to both of <code class="computeroutput"><span class="identifier">BinaryPredicate</span></code>'s 147 argument types. 148 </li> 149</ul></div> 150<h6> 151<a name="range.reference.algorithms.non_mutating.lower_bound.h4"></a> 152 <span class="phrase"><a name="range.reference.algorithms.non_mutating.lower_bound.precondition_"></a></span><a class="link" href="lower_bound.html#range.reference.algorithms.non_mutating.lower_bound.precondition_">Precondition:</a> 153 </h6> 154<p> 155 <span class="bold"><strong>For the non-predicate versions:</strong></span> 156 </p> 157<p> 158 <code class="computeroutput"><span class="identifier">rng</span></code> is sorted in ascending 159 order according to <code class="computeroutput"><span class="keyword">operator</span><span class="special"><</span></code>. 160 </p> 161<p> 162 <span class="bold"><strong>For the predicate versions:</strong></span> 163 </p> 164<p> 165 <code class="computeroutput"><span class="identifier">rng</span></code> is sorted in ascending 166 order according to <code class="computeroutput"><span class="identifier">pred</span></code>. 167 </p> 168<h6> 169<a name="range.reference.algorithms.non_mutating.lower_bound.h5"></a> 170 <span class="phrase"><a name="range.reference.algorithms.non_mutating.lower_bound.complexity"></a></span><a class="link" href="lower_bound.html#range.reference.algorithms.non_mutating.lower_bound.complexity">Complexity</a> 171 </h6> 172<p> 173 For ranges that model the <a class="link" href="../../../concepts/random_access_range.html" title="Random Access Range">Random 174 Access Range</a> concept the complexity is <code class="computeroutput"><span class="identifier">O</span><span class="special">(</span><span class="identifier">log</span> <span class="identifier">N</span><span class="special">)</span></code>, 175 where <code class="computeroutput"><span class="identifier">N</span></code> is <code class="computeroutput"><span class="identifier">distance</span><span class="special">(</span><span class="identifier">rng</span><span class="special">)</span></code>. 176 </p> 177<p> 178 For all other range types the complexity is <code class="computeroutput"><span class="identifier">O</span><span class="special">(</span><span class="identifier">N</span><span class="special">)</span></code>. 179 </p> 180</div> 181<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 182<td align="left"></td> 183<td align="right"><div class="copyright-footer">Copyright © 2003-2010 Thorsten Ottosen, 184 Neil Groves<p> 185 Distributed under the Boost Software License, Version 1.0. (See accompanying 186 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>) 187 </p> 188</div></td> 189</tr></table> 190<hr> 191<div class="spirit-nav"> 192<a accesskey="p" href="lexicographical_compare.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../non_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="max_element.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 193</div> 194</body> 195</html> 196
