title: sqrt() of int type in C
body: <p>I am programming in the c language on mac os x. I am using sqrt, from math.h, function like this:</p>
  
  <pre><code>int start = Data -&gt; start_number;
  double localSum;
  
  for (start; start &lt;= end; start++) {
      localSum += sqrt(start);
  }
  </code></pre>
  
  <p>This works, but why? and why am I getting no warning? On the man page for sqrt, it takes a double as parameter, but I give it an int - how can it work?</p>
  
  <p>Thanks</p>