How to access a map within a map in C++ ..? Performance issue?
<pre><code>typedef map&lt;int, string&gt; iMap;
typedef map&lt;double, innerMap&gt; OutMap;

OutMap mx;

map&lt;double, iMap &gt;::iterator it_out;
map&lt;int, string&gt;::iterator it_i;

for ( it_out=mx.begin() ; it_out != mx.end(); it_out++ ) {
   cout &lt;&lt; "\n\nNew element\n" &lt;&lt; (*it_out).first &lt;&lt; endl;
   for( it_i=(*it_out).second.begin(); it_i != (*it_out).second.end(); it_out++)
     cout &lt;&lt; (*it_i).first &lt;&lt; " =&gt; " &lt;&lt; (*it_i).second &lt;&lt; endl;
}
</code></pre>

<p>I'm pretty sure the above code is fine...
Is there any performance issue...?</p>
