penter
static void penter(Node *);
penter(p1); /* enter parent pointers and leaf indices */
penter(left(p));
penter(left(p));
penter(right(p));
penter(p1); /* enter parent pointers and leaf indices */
penter(left(p));
penter(left(p));
penter(right(p));
static void penter(NODE *p);