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begin [C++ Reference]
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<h2><a name="begin" id="begin">begin</a></h2>
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<p>
Syntax:
</p>
<pre class="c code c++" style="font-family:monospace;"> <span class="co2">#include <string></span>
iterator begin<span class="br0">(</span><span class="br0">)</span><span class="sy0">;</span>
const_iterator begin<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy0">;</span></pre>
<p>
The function begin() returns an iterator to the first element of the string.
begin() should run in <a href="../complexity.html" class="wikilink1" title="complexity">constant time</a>.
For example, the following code uses begin() to initialize an iterator that is
used to traverse a list:
</p>
<pre class="c code c++" style="font-family:monospace;"> <span class="co1">// Create a list of characters</span>
list<span class="sy0"><</span>char<span class="sy0">></span> charList<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>
<span class="kw4">static</span> <span class="kw4">const</span> <span class="kw4">char</span> letters<span class="br0">[</span><span class="br0">]</span> <span class="sy0">=</span> <span class="st0">"ABCDEFGHIJ"</span><span class="sy0">;</span>
charList.<span class="me1">push_front</span><span class="br0">(</span> letters<span class="br0">[</span>i<span class="br0">]</span> <span class="br0">)</span><span class="sy0">;</span>
<span class="br0">}</span>
<span class="co1">// Display the list</span>
list<span class="sy0"><</span>char<span class="sy0">>::</span><span class="me2">iterator</span> theIterator<span class="sy0">;</span>
<span class="kw1">for</span> <span class="br0">(</span> theIterator <span class="sy0">=</span> charList.<span class="me1">begin</span><span class="br0">(</span><span class="br0">)</span><span class="sy0">;</span>
theIterator <span class="sy0">!=</span> charList.<span class="me1">end</span><span class="br0">(</span><span class="br0">)</span><span class="sy0">;</span>
<span class="sy0">++</span>theIterator <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="sy0">*</span>theIterator<span class="sy0">;</span>
<span class="br0">}</span></pre>
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Related Topics: <a href="../string/end.html" class="wikilink1" title="string:end">end</a>, <a href="../string/rbegin.html" class="wikilink1" title="string:rbegin">rbegin</a>, <a href="../string/rend.html" class="wikilink1" title="string:rend">rend</a>
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