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find_if [C++ Reference]
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<h2><a name="find_if" id="find_if">find_if</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_if<span class="br0">(</span> input_iterator start<span class="sy0">,</span> input_iterator end<span class="sy0">,</span> UnPred up <span class="br0">)</span><span class="sy0">;</span></pre>
<p>
The find_if() function searches for the first element between start and end for
which the unary predicate up returns true.
</p>
<p>
If such an element is found, an iterator pointing to that element is returned.
Otherwise, an iterator pointing to end is returned.
</p>
<p>
For example, the following code uses find_if() and a “greater-than-zero” unary
predicate to find the first positive, non-zero number in a list of numbers:
</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> 0<span class="sy0">,</span> <span class="sy0">-</span>1<span class="sy0">,</span> <span class="sy0">-</span>2<span class="sy0">,</span> <span class="sy0">-</span>3<span class="sy0">,</span> <span class="sy0">-</span>4<span class="sy0">,</span> 342<span class="sy0">,</span> <span class="sy0">-</span>5 <span class="br0">}</span><span class="sy0">;</span>
<span class="kw4">int</span><span class="sy0">*</span> result<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">7</span><span class="sy0">;</span>
result <span class="sy0">=</span> find_if<span class="br0">(</span> nums <span class="sy0">+</span> start<span class="sy0">,</span> nums <span class="sy0">+</span> end<span class="sy0">,</span> bind2nd<span class="br0">(</span>greater<span class="sy0"><</span>int<span class="sy0">></span><span class="br0">(</span><span class="br0">)</span><span class="sy0">,</span> 0<span class="br0">)</span><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 greater than zero"</span> <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 positive non-zero 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/equal.html" class="wikilink1" title="stl:algorithm:equal">equal</a>, <a href="../../stl/algorithm/find.html" class="wikilink1" title="stl:algorithm:find">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/search_n.html" class="wikilink1" title="stl:algorithm:search_n">search_n</a>
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