title: padding with sprintf
body: <p>I have a dummy question. I would like to print an integer into a buffer padding with 0 but I cannot sort it out the <code>sprintf</code>format.
  I am trying the following</p>
  
  <pre><code>char buf[31];
  int my_val = 324;
  sprintf( buf, "%d030", my_val );
  </code></pre>
  
  <p>hoping to have the following string</p>
  
  <pre><code>"000000000000000000000000000324"
  </code></pre>
  
  <p>what am I doing wrong? It doesn't mean pad with 0 for a max width of 30 chars? </p>