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find [C++ Reference]
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<h2><a name="find" id="find">find</a></h2>
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<p>
Syntax:
</p>
<pre class="c code c++" style="font-family:monospace;"> <span class="co2">#include <algorithm></span>
input_iterator find<span class="br0">(</span> input_iterator start<span class="sy0">,</span> input_iterator end<span class="sy0">,</span> <span class="kw4">const</span> TYPE<span class="sy0">&</span> val <span class="br0">)</span><span class="sy0">;</span></pre>
<p>
The find() algorithm looks for an element matching <code>val</code> between <code>start</code> and <code>end</code>.
If an element matching <code>val</code> is found, the return value is an iterator that
points to that element. Otherwise, the return value is an iterator that points
to <code>end</code>.
</p>
<p>
For example, the following code uses find to search a <a href="../../stl/vector/start.html" class="wikilink1" title="stl:vector:start">vector</a> of integers for
the number 3:
</p>
<pre class="c code c++" style="font-family:monospace;"> <span class="kw4">int</span> num_to_find <span class="sy0">=</span> <span class="nu0">3</span><span class="sy0">;</span>
vector<span class="sy0"><</span>int<span class="sy0">></span> v1<span class="sy0">;</span>
<span class="kw1">for</span><span class="br0">(</span> <span class="kw4">int</span> i <span class="sy0">=</span> <span class="nu0">0</span><span class="sy0">;</span> i <span class="sy0"><</span> <span class="nu0">10</span><span class="sy0">;</span> i<span class="sy0">++</span> <span class="br0">)</span> <span class="br0">{</span>
v1.<span class="me1">push_back</span><span class="br0">(</span>i<span class="br0">)</span><span class="sy0">;</span>
<span class="br0">}</span>
vector<span class="sy0"><</span>int<span class="sy0">>::</span><span class="me2">iterator</span> result<span class="sy0">;</span>
result <span class="sy0">=</span> find<span class="br0">(</span> v1.<span class="me1">begin</span><span class="br0">(</span><span class="br0">)</span><span class="sy0">,</span> v1.<span class="me1">end</span><span class="br0">(</span><span class="br0">)</span><span class="sy0">,</span> num_to_find <span class="br0">)</span><span class="sy0">;</span>
<span class="kw1">if</span><span class="br0">(</span> result <span class="sy0">==</span> v1.<span class="me1">end</span><span class="br0">(</span><span class="br0">)</span> <span class="br0">)</span> <span class="br0">{</span>
<a href="http://www.opengroup.org/onlinepubs/009695399/functions/cout.html"><span class="kw3">cout</span></a> <span class="sy0"><<</span> <span class="st0">"Did not find any element matching "</span> <span class="sy0"><<</span> num_to_find <span class="sy0"><<</span> endl<span class="sy0">;</span>
<span class="br0">}</span>
<span class="kw1">else</span> <span class="br0">{</span>
<a href="http://www.opengroup.org/onlinepubs/009695399/functions/cout.html"><span class="kw3">cout</span></a> <span class="sy0"><<</span> <span class="st0">"Found a matching element: "</span> <span class="sy0"><<</span> <span class="sy0">*</span>result <span class="sy0"><<</span> endl<span class="sy0">;</span>
<span class="br0">}</span></pre>
<p>
In the next example, shown below, the find function is used on an array of
integers. This example shows how the C++ STL algorithms can be used to manipulate
arrays and pointers in the same manner that they manipulate containers and
iterators:
</p>
<pre class="c code c++" style="font-family:monospace;"> <span class="kw4">int</span> nums<span class="br0">[</span><span class="br0">]</span> <span class="sy0">=</span> <span class="br0">{</span> 3<span class="sy0">,</span> 1<span class="sy0">,</span> 4<span class="sy0">,</span> 1<span class="sy0">,</span> 5<span class="sy0">,</span> 9 <span class="br0">}</span><span class="sy0">;</span>
<span class="kw4">int</span> num_to_find <span class="sy0">=</span> <span class="nu0">5</span><span class="sy0">;</span>
<span class="kw4">int</span> start <span class="sy0">=</span> <span class="nu0">0</span><span class="sy0">;</span>
<span class="kw4">int</span> end <span class="sy0">=</span> <span class="nu0">2</span><span class="sy0">;</span>
<span class="kw4">int</span><span class="sy0">*</span> result <span class="sy0">=</span> find<span class="br0">(</span> nums <span class="sy0">+</span> start<span class="sy0">,</span> nums <span class="sy0">+</span> end<span class="sy0">,</span> num_to_find <span class="br0">)</span><span class="sy0">;</span>
<span class="kw1">if</span><span class="br0">(</span> result <span class="sy0">==</span> nums <span class="sy0">+</span> end <span class="br0">)</span> <span class="br0">{</span>
<a href="http://www.opengroup.org/onlinepubs/009695399/functions/cout.html"><span class="kw3">cout</span></a> <span class="sy0"><<</span> <span class="st0">"Did not find any number matching "</span> <span class="sy0"><<</span> num_to_find <span class="sy0"><<</span> endl<span class="sy0">;</span>
<span class="br0">}</span> <span class="kw1">else</span> <span class="br0">{</span>
<a href="http://www.opengroup.org/onlinepubs/009695399/functions/cout.html"><span class="kw3">cout</span></a> <span class="sy0"><<</span> <span class="st0">"Found a matching number: "</span> <span class="sy0"><<</span> <span class="sy0">*</span>result <span class="sy0"><<</span> endl<span class="sy0">;</span>
<span class="br0">}</span></pre>
<p>
Related Topics: <a href="../../stl/algorithm/adjacent_find.html" class="wikilink1" title="stl:algorithm:adjacent_find">adjacent_find</a>, <a href="../../stl/algorithm/find_end.html" class="wikilink1" title="stl:algorithm:find_end">find_end</a>, <a href="../../stl/algorithm/find_first_of.html" class="wikilink1" title="stl:algorithm:find_first_of">find_first_of</a>, <a href="../../stl/algorithm/find_if.html" class="wikilink1" title="stl:algorithm:find_if">find_if</a>, <a href="../../stl/algorithm/mismatch.html" class="wikilink1" title="stl:algorithm:mismatch">mismatch</a>, <a href="../../stl/algorithm/search.html" class="wikilink1" title="stl:algorithm:search">search</a>
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