/* strlen:  return length of string s */
   int strlen(char *s)
   {
       int n;

       for (n = 0; *s != '\0', s++)
           n++;
       return n;
   }
/* strlen:  return length of string s
   int strlen(char *s)
   {
       char *p = s;

       while (*p != '\0')
           p++;
       return p - s;
   }

*/