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  25 <div class="section">
  26 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
  27 <a name="algorithm.CXX14"></a><a class="link" href="CXX14.html" title="C++14 Algorithms">C++14 Algorithms</a>
  28 </h2></div></div></div>
  29 <div class="toc"><dl class="toc">
  30 <dt><span class="section"><a href="CXX14.html#algorithm.CXX14.CXX14_inner_algorithms"></a></span></dt>
  31 <dd><dl>
  32 <dt><span class="section"><a href="CXX14.html#the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.equal">equal
  33         </a></span></dt>
  34 <dt><span class="section"><a href="CXX14.html#the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.mismatch">mismatch
  35         </a></span></dt>
  36 </dl></dd>
  37 </dl></div>
  38 <div class="section">
  39 <div class="titlepage"></div>
  40 <div class="section">
  41 <div class="titlepage"><div><div><h4 class="title">
  42 <a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.equal"></a><a class="link" href="CXX14.html#the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.equal" title="equal">equal
  43         </a>
  44 </h4></div></div></div>
  45 <p>
  46           The header file 'equal.hpp' contains two variants of a the stl algorithm
  47           <code class="computeroutput"><span class="identifier">equal</span></code>. The algorithm tests
  48           to see if two sequences contain equal values;
  49         </p>
  50 <p>
  51           Before (the proposed) C++14 the algorithm <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">equal</span></code>
  52           took three iterators and an optional comparison predicate. The first two
  53           iterators <code class="computeroutput"><span class="special">[</span><span class="identifier">first1</span><span class="special">,</span> <span class="identifier">last1</span><span class="special">)</span></code> defined a sequence, and the second one
  54           <code class="computeroutput"><span class="identifier">first2</span></code> defined the start
  55           of the second sequence. The second sequence was assumed to be the same
  56           length as the first.
  57         </p>
  58 <p>
  59           In C++14, two new variants were introduced, taking four iterators and an
  60           optional comparison predicate. The four iterators define two sequences
  61           <code class="computeroutput"><span class="special">[</span><span class="identifier">first1</span><span class="special">,</span> <span class="identifier">last1</span><span class="special">)</span></code> and <code class="computeroutput"><span class="special">[</span><span class="identifier">first2</span><span class="special">,</span> <span class="identifier">last2</span><span class="special">)</span></code>
  62           explicitly, rather than defining the second one implicitly. This leads
  63           to correct answers in more cases (and avoid undefined behavior in others).
  64         </p>
  65 <p>
  66           Consider the two sequences:
  67 </p>
  68 <pre class="programlisting"><span class="keyword">auto</span> <span class="identifier">seq1</span> <span class="special">=</span> <span class="special">{</span> <span class="number">0</span><span class="special">,</span> <span class="number">1</span><span class="special">,</span> <span class="number">2</span> <span class="special">};</span>
  69 <span class="keyword">auto</span> <span class="identifier">seq2</span> <span class="special">=</span> <span class="special">{</span> <span class="number">0</span><span class="special">,</span> <span class="number">1</span><span class="special">,</span> <span class="number">2</span><span class="special">,</span> <span class="number">3</span><span class="special">,</span> <span class="number">4</span> <span class="special">};</span>
  70
  71 <span class="identifier">std</span><span class="special">::</span><span class="identifier">equal</span> <span class="special">(</span> <span class="identifier">seq1</span><span class="special">.</span><span class="identifier">begin</span> <span class="special">(),</span> <span class="identifier">seq1</span><span class="special">.</span><span class="identifier">end</span> <span class="special">(),</span> <span class="identifier">seq2</span><span class="special">.</span><span class="identifier">begin</span> <span class="special">());</span> <span class="comment">// true</span>
  72 <span class="identifier">std</span><span class="special">::</span><span class="identifier">equal</span> <span class="special">(</span> <span class="identifier">seq2</span><span class="special">.</span><span class="identifier">begin</span> <span class="special">(),</span> <span class="identifier">seq2</span><span class="special">.</span><span class="identifier">end</span> <span class="special">(),</span> <span class="identifier">seq1</span><span class="special">.</span><span class="identifier">begin</span> <span class="special">());</span> <span class="comment">// Undefined behavior</span>
  73 <span class="identifier">std</span><span class="special">::</span><span class="identifier">equal</span> <span class="special">(</span> <span class="identifier">seq1</span><span class="special">.</span><span class="identifier">begin</span> <span class="special">(),</span> <span class="identifier">seq1</span><span class="special">.</span><span class="identifier">end</span> <span class="special">(),</span> <span class="identifier">seq2</span><span class="special">.</span><span class="identifier">begin</span> <span class="special">(),</span> <span class="identifier">seq2</span><span class="special">.</span><span class="identifier">end</span> <span class="special">());</span> <span class="comment">// false</span>
  74 </pre>
  75 <p>
  76         </p>
  77 <p>
  78           You can argue that <code class="computeroutput"><span class="keyword">true</span></code> is
  79           the correct answer in the first case, even though the sequences are not
  80           the same. The first N entries in <code class="computeroutput"><span class="identifier">seq2</span></code>
  81           are the same as the entries in <code class="computeroutput"><span class="identifier">seq1</span></code>
  82           - but that's not all that's in <code class="computeroutput"><span class="identifier">seq2</span></code>.
  83           But in the second case, the algorithm will read past the end of <code class="computeroutput"><span class="identifier">seq1</span></code>, resulting in undefined behavior
  84           (large earthquake, incorrect results, pregnant cat, etc).
  85         </p>
  86 <p>
  87           However, if the two sequences are specified completely, it's clear that
  88           they are not equal.
  89         </p>
  90 <h6>
  91 <a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.equal.h0"></a>
  92           <span class="phrase"><a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.equal.interface"></a></span><a class="link" href="CXX14.html#the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.equal.interface">interface</a>
  93         </h6>
  94 <p>
  95           The function <code class="computeroutput"><span class="identifier">equal</span></code> returns
  96           true if the two sequences compare equal; i.e, if each element in the sequence
  97           compares equal to the corresponding element in the other sequence. One
  98           version uses <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">equal_to</span></code> to do the comparison; the other
  99           lets the caller pass predicate to do the comparisons.
 100         </p>
 101 <p>
 102 </p>
 103 <pre class="programlisting"><span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">InputIterator1</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">InputIterator2</span><span class="special">&gt;</span>
 104 <span class="keyword">bool</span> <span class="identifier">equal</span> <span class="special">(</span> <span class="identifier">InputIterator1</span> <span class="identifier">first1</span><span class="special">,</span> <span class="identifier">InputIterator1</span> <span class="identifier">last1</span><span class="special">,</span>
 105              <span class="identifier">InputIterator2</span> <span class="identifier">first2</span><span class="special">,</span> <span class="identifier">InputIterator2</span> <span class="identifier">last2</span> <span class="special">);</span>
 106
 107 <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">InputIterator1</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">InputIterator2</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">BinaryPredicate</span><span class="special">&gt;</span>
 108 <span class="keyword">bool</span> <span class="identifier">equal</span> <span class="special">(</span> <span class="identifier">InputIterator1</span> <span class="identifier">first1</span><span class="special">,</span> <span class="identifier">InputIterator1</span> <span class="identifier">last1</span><span class="special">,</span>
 109              <span class="identifier">InputIterator2</span> <span class="identifier">first2</span><span class="special">,</span> <span class="identifier">InputIterator2</span> <span class="identifier">last2</span><span class="special">,</span> <span class="identifier">BinaryPredicate</span> <span class="identifier">pred</span> <span class="special">);</span>
 110 </pre>
 111 <p>
 112         </p>
 113 <h6>
 114 <a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.equal.h1"></a>
 115           <span class="phrase"><a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.equal.examples"></a></span><a class="link" href="CXX14.html#the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.equal.examples">Examples</a>
 116         </h6>
 117 <p>
 118           Given the container <code class="computeroutput"><span class="identifier">c1</span></code>
 119           containing <code class="computeroutput"><span class="special">{</span> <span class="number">0</span><span class="special">,</span> <span class="number">1</span><span class="special">,</span>
 120           <span class="number">2</span><span class="special">,</span> <span class="number">3</span><span class="special">,</span> <span class="number">14</span><span class="special">,</span> <span class="number">15</span> <span class="special">}</span></code>,
 121           and <code class="computeroutput"><span class="identifier">c2</span></code> containing <code class="computeroutput"><span class="special">{</span> <span class="number">1</span><span class="special">,</span>
 122           <span class="number">2</span><span class="special">,</span> <span class="number">3</span> <span class="special">}</span></code>, then
 123 </p>
 124 <pre class="programlisting"><span class="identifier">equal</span> <span class="special">(</span> <span class="identifier">c1</span><span class="special">.</span><span class="identifier">begin</span> <span class="special">(),</span>     <span class="identifier">c1</span><span class="special">.</span><span class="identifier">end</span> <span class="special">(),</span>       <span class="identifier">c2</span><span class="special">.</span><span class="identifier">begin</span> <span class="special">(),</span> <span class="identifier">c2</span><span class="special">.</span><span class="identifier">end</span> <span class="special">())</span> <span class="special">--&gt;</span> <span class="keyword">false</span>
 125 <span class="identifier">equal</span> <span class="special">(</span> <span class="identifier">c1</span><span class="special">.</span><span class="identifier">begin</span> <span class="special">()</span> <span class="special">+</span> <span class="number">1</span><span class="special">,</span> <span class="identifier">c1</span><span class="special">.</span><span class="identifier">begin</span> <span class="special">()</span> <span class="special">+</span> <span class="number">3</span><span class="special">,</span> <span class="identifier">c2</span><span class="special">.</span><span class="identifier">begin</span> <span class="special">(),</span> <span class="identifier">c2</span><span class="special">.</span><span class="identifier">end</span> <span class="special">())</span> <span class="special">--&gt;</span> <span class="keyword">true</span>
 126 <span class="identifier">equal</span> <span class="special">(</span> <span class="identifier">c1</span><span class="special">.</span><span class="identifier">end</span> <span class="special">(),</span>       <span class="identifier">c1</span><span class="special">.</span><span class="identifier">end</span> <span class="special">(),</span>       <span class="identifier">c2</span><span class="special">.</span><span class="identifier">end</span> <span class="special">(),</span>   <span class="identifier">c2</span><span class="special">.</span><span class="identifier">end</span> <span class="special">())</span> <span class="special">--&gt;</span> <span class="keyword">true</span>  <span class="comment">// empty sequences are alway equal to each other</span>
 127 </pre>
 128 <p>
 129         </p>
 130 <h6>
 131 <a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.equal.h2"></a>
 132           <span class="phrase"><a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.equal.iterator_requirements"></a></span><a class="link" href="CXX14.html#the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.equal.iterator_requirements">Iterator
 133           Requirements</a>
 134         </h6>
 135 <p>
 136           <code class="computeroutput"><span class="identifier">equal</span></code> works on all iterators
 137           except output iterators.
 138         </p>
 139 <h6>
 140 <a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.equal.h3"></a>
 141           <span class="phrase"><a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.equal.complexity"></a></span><a class="link" href="CXX14.html#the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.equal.complexity">Complexity</a>
 142         </h6>
 143 <p>
 144           Both of the variants of <code class="computeroutput"><span class="identifier">equal</span></code>
 145           run in <span class="emphasis"><em>O(N)</em></span> (linear) time; that is, they compare against
 146           each element in the list once. If the sequence is found to be not equal
 147           at any point, the routine will terminate immediately, without examining
 148           the rest of the elements.
 149         </p>
 150 <h6>
 151 <a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.equal.h4"></a>
 152           <span class="phrase"><a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.equal.exception_safety"></a></span><a class="link" href="CXX14.html#the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.equal.exception_safety">Exception
 153           Safety</a>
 154         </h6>
 155 <p>
 156           Both of the variants of <code class="computeroutput"><span class="identifier">equal</span></code>
 157           take their parameters by value and do not depend upon any global state.
 158           Therefore, all the routines in this file provide the strong exception guarantee.
 159         </p>
 160 <h6>
 161 <a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.equal.h5"></a>
 162           <span class="phrase"><a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.equal.notes"></a></span><a class="link" href="CXX14.html#the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.equal.notes">Notes</a>
 163         </h6>
 164 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
 165 <li class="listitem">
 166               The four iterator version of the routine <code class="computeroutput"><span class="identifier">equal</span></code>
 167               is part of the C++14 standard. When C++14 standard library implementations
 168               become available, the implementation from the standard library should
 169               be used.
 170             </li>
 171 <li class="listitem">
 172               <code class="computeroutput"><span class="identifier">equal</span></code> returns true
 173               for two empty ranges, no matter what predicate is passed to test against.
 174             </li>
 175 </ul></div>
 176 </div>
 177 <div class="section">
 178 <div class="titlepage"><div><div><h4 class="title">
 179 <a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.mismatch"></a><a class="link" href="CXX14.html#the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.mismatch" title="mismatch">mismatch
 180         </a>
 181 </h4></div></div></div>
 182 <p>
 183           The header file 'mismatch.hpp' contains two variants of a the stl algorithm
 184           <code class="computeroutput"><span class="identifier">mismatch</span></code>. The algorithm
 185           finds the first point in two sequences where they do not match.
 186         </p>
 187 <p>
 188           Before (the proposed) C++14 the algorithm <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">mismatch</span></code>
 189           took three iterators and an optional comparison predicate. The first two
 190           iterators <code class="computeroutput"><span class="special">[</span><span class="identifier">first1</span><span class="special">,</span> <span class="identifier">last1</span><span class="special">)</span></code> defined a sequence, and the second one
 191           <code class="computeroutput"><span class="identifier">first2</span></code> defined the start
 192           of the second sequence. The second sequence was assumed to be the same
 193           length as the first.
 194         </p>
 195 <p>
 196           In C++14, two new variants were introduced, taking four iterators and an
 197           optional comparison predicate. The four iterators define two sequences
 198           <code class="computeroutput"><span class="special">[</span><span class="identifier">first1</span><span class="special">,</span> <span class="identifier">last1</span><span class="special">)</span></code> and <code class="computeroutput"><span class="special">[</span><span class="identifier">first2</span><span class="special">,</span> <span class="identifier">last2</span><span class="special">)</span></code>
 199           explicitly, rather than defining the second one implicitly. This leads
 200           to correct answers in more cases (and avoid undefined behavior in others).
 201         </p>
 202 <p>
 203           Consider the two sequences:
 204 </p>
 205 <pre class="programlisting"><span class="keyword">auto</span> <span class="identifier">seq1</span> <span class="special">=</span> <span class="special">{</span> <span class="number">0</span><span class="special">,</span> <span class="number">1</span><span class="special">,</span> <span class="number">2</span> <span class="special">};</span>
 206 <span class="keyword">auto</span> <span class="identifier">seq2</span> <span class="special">=</span> <span class="special">{</span> <span class="number">0</span><span class="special">,</span> <span class="number">1</span><span class="special">,</span> <span class="number">2</span><span class="special">,</span> <span class="number">3</span><span class="special">,</span> <span class="number">4</span> <span class="special">};</span>
 207
 208 <span class="identifier">std</span><span class="special">::</span><span class="identifier">mismatch</span> <span class="special">(</span> <span class="identifier">seq1</span><span class="special">.</span><span class="identifier">begin</span> <span class="special">(),</span> <span class="identifier">seq1</span><span class="special">.</span><span class="identifier">end</span> <span class="special">(),</span> <span class="identifier">seq2</span><span class="special">.</span><span class="identifier">begin</span> <span class="special">());</span> <span class="comment">// &lt;3, 3&gt;</span>
 209 <span class="identifier">std</span><span class="special">::</span><span class="identifier">mismatch</span> <span class="special">(</span> <span class="identifier">seq2</span><span class="special">.</span><span class="identifier">begin</span> <span class="special">(),</span> <span class="identifier">seq2</span><span class="special">.</span><span class="identifier">end</span> <span class="special">(),</span> <span class="identifier">seq1</span><span class="special">.</span><span class="identifier">begin</span> <span class="special">());</span> <span class="comment">// Undefined behavior</span>
 210 <span class="identifier">std</span><span class="special">::</span><span class="identifier">mismatch</span> <span class="special">(</span> <span class="identifier">seq1</span><span class="special">.</span><span class="identifier">begin</span> <span class="special">(),</span> <span class="identifier">seq1</span><span class="special">.</span><span class="identifier">end</span> <span class="special">(),</span> <span class="identifier">seq2</span><span class="special">.</span><span class="identifier">begin</span> <span class="special">(),</span> <span class="identifier">seq2</span><span class="special">.</span><span class="identifier">end</span> <span class="special">());</span> <span class="comment">// &lt;3, 3&gt;</span>
 211 </pre>
 212 <p>
 213         </p>
 214 <p>
 215           The first N entries in <code class="computeroutput"><span class="identifier">seq2</span></code>
 216           are the same as the entries in <code class="computeroutput"><span class="identifier">seq1</span></code>
 217           - but that's not all that's in <code class="computeroutput"><span class="identifier">seq2</span></code>.
 218           In the second case, the algorithm will read past the end of <code class="computeroutput"><span class="identifier">seq1</span></code>, resulting in undefined behavior
 219           (large earthquake, incorrect results, pregnant cat, etc).
 220         </p>
 221 <p>
 222           However, if the two sequences are specified completely, it's clear that
 223           where the mismatch occurs.
 224         </p>
 225 <h6>
 226 <a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.mismatch.h0"></a>
 227           <span class="phrase"><a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.mismatch.interface"></a></span><a class="link" href="CXX14.html#the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.mismatch.interface">interface</a>
 228         </h6>
 229 <p>
 230           The function <code class="computeroutput"><span class="identifier">mismatch</span></code> returns
 231           a pair of iterators which denote the first mismatching elements in each
 232           sequence. If the sequences match completely, <code class="computeroutput"><span class="identifier">mismatch</span></code>
 233           returns their end iterators. One version uses <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">equal_to</span></code>
 234           to do the comparison; the other lets the caller pass predicate to do the
 235           comparisons.
 236         </p>
 237 <p>
 238 </p>
 239 <pre class="programlisting"><span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">InputIterator1</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">InputIterator2</span><span class="special">&gt;</span>
 240 <span class="identifier">std</span><span class="special">::</span><span class="identifier">pair</span><span class="special">&lt;</span><span class="identifier">InputIterator1</span><span class="special">,</span> <span class="identifier">InputIterator2</span><span class="special">&gt;</span>
 241 <span class="identifier">mismatch</span> <span class="special">(</span> <span class="identifier">InputIterator1</span> <span class="identifier">first1</span><span class="special">,</span> <span class="identifier">InputIterator1</span> <span class="identifier">last1</span><span class="special">,</span>
 242            <span class="identifier">InputIterator2</span> <span class="identifier">first2</span><span class="special">,</span> <span class="identifier">InputIterator2</span> <span class="identifier">last2</span> <span class="special">);</span>
 243
 244 <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">InputIterator1</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">InputIterator2</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">BinaryPredicate</span><span class="special">&gt;</span>
 245 <span class="identifier">std</span><span class="special">::</span><span class="identifier">pair</span><span class="special">&lt;</span><span class="identifier">InputIterator1</span><span class="special">,</span> <span class="identifier">InputIterator2</span><span class="special">&gt;</span>
 246 <span class="identifier">mismatch</span> <span class="special">(</span> <span class="identifier">InputIterator1</span> <span class="identifier">first1</span><span class="special">,</span> <span class="identifier">InputIterator1</span> <span class="identifier">last1</span><span class="special">,</span>
 247            <span class="identifier">InputIterator2</span> <span class="identifier">first2</span><span class="special">,</span> <span class="identifier">InputIterator2</span> <span class="identifier">last2</span><span class="special">,</span> <span class="identifier">BinaryPredicate</span> <span class="identifier">pred</span> <span class="special">);</span>
 248 </pre>
 249 <p>
 250         </p>
 251 <h6>
 252 <a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.mismatch.h1"></a>
 253           <span class="phrase"><a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.mismatch.examples"></a></span><a class="link" href="CXX14.html#the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.mismatch.examples">Examples</a>
 254         </h6>
 255 <p>
 256           Given the container <code class="computeroutput"><span class="identifier">c1</span></code>
 257           containing <code class="computeroutput"><span class="special">{</span> <span class="number">0</span><span class="special">,</span> <span class="number">1</span><span class="special">,</span>
 258           <span class="number">2</span><span class="special">,</span> <span class="number">3</span><span class="special">,</span> <span class="number">14</span><span class="special">,</span> <span class="number">15</span> <span class="special">}</span></code>,
 259           and <code class="computeroutput"><span class="identifier">c2</span></code> containing <code class="computeroutput"><span class="special">{</span> <span class="number">1</span><span class="special">,</span>
 260           <span class="number">2</span><span class="special">,</span> <span class="number">3</span> <span class="special">}</span></code>, then
 261 </p>
 262 <pre class="programlisting"><span class="identifier">mismatch</span> <span class="special">(</span> <span class="identifier">c1</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span>     <span class="identifier">c1</span><span class="special">.</span><span class="identifier">end</span><span class="special">(),</span>       <span class="identifier">c2</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> <span class="identifier">c2</span><span class="special">.</span><span class="identifier">end</span><span class="special">())</span> <span class="special">--&gt;</span> <span class="special">&lt;</span><span class="identifier">c1</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> <span class="identifier">c2</span><span class="special">.</span><span class="identifier">begin</span><span class="special">()&gt;</span> <span class="comment">// first elements do not match</span>
 263 <span class="identifier">mismatch</span> <span class="special">(</span> <span class="identifier">c1</span><span class="special">.</span><span class="identifier">begin</span><span class="special">()</span> <span class="special">+</span> <span class="number">1</span><span class="special">,</span> <span class="identifier">c1</span><span class="special">.</span><span class="identifier">begin</span><span class="special">()</span> <span class="special">+</span> <span class="number">4</span><span class="special">,</span> <span class="identifier">c2</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> <span class="identifier">c2</span><span class="special">.</span><span class="identifier">end</span><span class="special">())</span> <span class="special">--&gt;</span> <span class="special">&lt;</span><span class="identifier">c1</span><span class="special">.</span><span class="identifier">begin</span><span class="special">()</span> <span class="special">+</span> <span class="number">4</span><span class="special">,</span> <span class="identifier">c2</span><span class="special">.</span><span class="identifier">end</span> <span class="special">()&gt;</span> <span class="comment">// all elements of `c2` match</span>
 264 <span class="identifier">mismatch</span> <span class="special">(</span> <span class="identifier">c1</span><span class="special">.</span><span class="identifier">end</span><span class="special">(),</span>       <span class="identifier">c1</span><span class="special">.</span><span class="identifier">end</span><span class="special">(),</span>       <span class="identifier">c2</span><span class="special">.</span><span class="identifier">end</span><span class="special">(),</span>   <span class="identifier">c2</span><span class="special">.</span><span class="identifier">end</span><span class="special">())</span> <span class="special">--&gt;</span> <span class="special">&lt;</span><span class="identifier">c1</span><span class="special">.</span><span class="identifier">end</span><span class="special">(),</span> <span class="identifier">c2</span><span class="special">.</span><span class="identifier">end</span><span class="special">()&gt;</span> <span class="comment">// empty sequences don't match at the end.</span>
 265 </pre>
 266 <p>
 267         </p>
 268 <h6>
 269 <a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.mismatch.h2"></a>
 270           <span class="phrase"><a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.mismatch.iterator_requirements"></a></span><a class="link" href="CXX14.html#the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.mismatch.iterator_requirements">Iterator
 271           Requirements</a>
 272         </h6>
 273 <p>
 274           <code class="computeroutput"><span class="identifier">mismatch</span></code> works on all iterators
 275           except output iterators.
 276         </p>
 277 <h6>
 278 <a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.mismatch.h3"></a>
 279           <span class="phrase"><a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.mismatch.complexity"></a></span><a class="link" href="CXX14.html#the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.mismatch.complexity">Complexity</a>
 280         </h6>
 281 <p>
 282           Both of the variants of <code class="computeroutput"><span class="identifier">mismatch</span></code>
 283           run in <span class="emphasis"><em>O(N)</em></span> (linear) time; that is, they compare against
 284           each element in the list once. If the sequence is found to be not equal
 285           at any point, the routine will terminate immediately, without examining
 286           the rest of the elements.
 287         </p>
 288 <h6>
 289 <a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.mismatch.h4"></a>
 290           <span class="phrase"><a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.mismatch.exception_safety"></a></span><a class="link" href="CXX14.html#the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.mismatch.exception_safety">Exception
 291           Safety</a>
 292         </h6>
 293 <p>
 294           Both of the variants of <code class="computeroutput"><span class="identifier">mismatch</span></code>
 295           take their parameters by value and do not depend upon any global state.
 296           Therefore, all the routines in this file provide the strong exception guarantee.
 297         </p>
 298 <h6>
 299 <a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.mismatch.h5"></a>
 300           <span class="phrase"><a name="the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.mismatch.notes"></a></span><a class="link" href="CXX14.html#the_boost_algorithm_library.CXX14.CXX14_inner_algorithms.mismatch.notes">Notes</a>
 301         </h6>
 302 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
 303 <li class="listitem">
 304               If the sequences are equal (or both are empty), then mismatch returns
 305               the end iterators of both sequences.
 306             </li>
 307 <li class="listitem">
 308               The four iterator version of the routine <code class="computeroutput"><span class="identifier">mismatch</span></code>
 309               is part of the C++14 standard. When C++14 standard library implementations
 310               become available, the implementation from the standard library should
 311               be used.
 312             </li>
 313 </ul></div>
 314 </div>
 315 </div>
 316 </div>
 317 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 318 <td align="left"></td>
 319 <td align="right"><div class="copyright-footer">Copyright &#169; 2010-2012 Marshall Clow<p>
 320         Distributed under the Boost Software License, Version 1.0. (See accompanying
 321         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>)
 322       </p>
 323 </div></td>
 324 </tr></table>
 325 <hr>
 326 <div class="spirit-nav">
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