What is the purpose of defining just one class in any header file and not inclulding the entire header file containing such class?
<p>For example I have found in some headers that there are some classes declarations in there like: </p>

<pre><code>#include "blabla.h"
#include "mehmeh.h" 
class myClass; 

/*

Some code using myClass 

*/
</code></pre>

<p>so what is the purpose of using this kind of declaration? </p>

<p>Thanks in advance for any comment </p>
