Return constant and non constant by value
<p>There is such code:</p>

<pre><code>   const int fun(){ return 2; } // can be assigned to int and const int
   int fun2(){ return 2; } // can be assigned to int and const int
</code></pre>

<p>Is there any difference in using these functions? They both return by value so it is always copied at the end of function call.</p>
