/*
 * This code is from "Algorithms in C, Third Edition,"
 * by Robert Sedgewick, Addison Wesley Longman, 1998.
 */
void traverse(link h)
  {
    QUEUEinit(max); QUEUEput(h);
    while (!QUEUEempty())
      {
        printf("%c ", (h = STACKpop())->token); 
            /* assumindo que token 'e um caracter... */
        if (h->l != NULL) QUEUEput(h->l); 
        if (h->r != NULL) QUEUEput(h->r); 
      }
  }