title: Parse a String in C
body: <p>Using just C</p>
  
  <p>I would like to parse a string and:</p>
  
  <ol>
  <li>count the occurrences of a character in a string (for example, count all the <code>'e'</code>s in a passed in string)</li>
  <li>Once counted (or even as I am counting) replace the e's with 3's</li>
  </ol>