title: Why do we need argc while there is always a null at the end of argv?
body: <p>It seems that the <code>argv[argc]</code> is always <code>NULL</code>, so I think we can traverse the argument list without <code>argc</code>. A single <code>while</code> loop will do this.</p>
  
  <p>If there is always a <code>NULL</code> at the end of <code>argv</code>, why do we need an <code>argc</code>?</p>