title: Is argv[argc] equal to NULL Pointer
body: <p>I read an article (forgot the URL), which said that <code>argv[argc]</code> is a <code>NULL</code> pointer (contains <code>\0</code>). To check whether if its true I wrote this code, yeah it exist. What I don't understand is, why does the OS include this <code>NULL</code> pointer at <code>argv[argc]</code>. Is it useful for something else also?</p>
  
  <pre><code>int
  main (int argc, char **argv){
  
      while (*argv)
          printf ("%s\n", *argv++);
  
      return 0;
  }
  </code></pre>