17 typedef struct node_t {  struct
19     struct node_t *left, *right;  argument
31     if (rootp == (struct node_t **)0)  in tsearch()
33     while (*rootp != (struct node_t *)0) {	/* Knuth's T1: */  in tsearch()
43     if (q != (struct node_t *)0) {	/* make new node */  in tsearch()
46 	q->left = q->right = (struct node_t *)0;  in tsearch()
63     if (rootp == (struct node_t **)0 || *rootp == (struct node_t *)0)  in tdelete()
64 	return ((struct node_t *)0);  in tdelete()
70 	if (*rootp == (struct node_t *)0)  in tdelete()
74     if ((q = (*rootp)->left) == (struct node_t *)0)	/* Left (struct node_t *)0? */  in tdelete()
76     else if (r != (struct node_t *)0) {		/* Right link is null? */  in tdelete()
77 	if (r->left == (struct node_t *)0) {	/* D2: Find successor */  in tdelete()
81 	    for (q = r->left; q->left != (struct node_t *)0; q = r->left)  in tdelete()
88     free((struct node_t *) *rootp);	/* D4: Free node */  in tdelete()
97     if (root->left == (struct node_t *)0 && root->right == (struct node_t *)0)  in trecurse()
101 	if (root->left != (struct node_t *)0)  in trecurse()
104 	if (root->right != (struct node_t *)0)  in trecurse()