title: Convert int to string in standard C
body: <p>I'm new to C.</p>
  
  <p>I'm looking for an example where I could call a function to convert <code>int</code> to string. I found <code>itoa</code>but this is not part of standard C.</p>
  
  <p>I also found <code>sprintf(str, "%d", aInt);</code> but the problem is that I don't know the size of the required str. Hence, how could I pass the right size for the output string</p>