/*Copyright (C) 1992, 1995 by Thomas Glen Smith.  All Rights Reserved.*/
/* avltsub3.h APL2 V1.0.0 **********************************************
* Included in avltree.c - tree is unbalanced - determine rotation.     *
***********************************************************************/
	if (d == +1) /* left imbalance? */
		if (b->avlbf == +1) { /* rotation type ll */
			a->left_child = b->rite_child;
			b->rite_child = a;
			a->avlbf = b->avlbf = 0;
		} else { /* rotation type lr */
			c = b->rite_child;
			if (c == NULL) cl = cr = NULL;
			else {
				cl = c->left_child;
				cr = c->rite_child;
			}
			b->rite_child = cl;
			a->left_child = cr;
			c->left_child = b;
			c->rite_child = a;
			switch (c->avlbf) {
				case +1: /* lr(b) */
					a->avlbf = -1;
					b->avlbf = 0;
					break;
				case -1: /* lr(c) */
					b->avlbf = +1;
					a->avlbf = 0;
					break;
				default:
					b->avlbf = a->avlbf = 0;
					break;
			} /* end switch */
			c->avlbf = 0;
			b = c;
		}