title: Include .cpp instead of header(.h)
body: <p>There are some cases when we include .cpp file instead of standard header file (.h), for example:</p>
  
  <pre><code>#include "example.cpp"
  </code></pre>
  
  <p>instead of</p>
  
  <pre><code>#include "example.h"
  </code></pre>
  
  <p>It seems to work but is this safe or should I avoid it?</p>
  
  <p>What about the compilation time?</p>