void find(char *s, char c) {
int n = strlen(s);
int ge = fine_ge(n, s, c);
int le = find_le(n, s, c);
printf("%s\n", s);
printf(" %d %c <= %c\n", le, c, s[le]);
printf(" %d %c >= %c\n", ge, c, s[ge]);
}
/* find greatest point in subtree p that is <= k */
static rb_node *find_le(rb_node *p, rb_key k, rb_tree *t)
{
rb_compare compare = t->compare;
while (p != NIL) {
if (compare(p->k, k) <= 0) { /* p->k <= k */
rb_node *r = find_le(p->r, k, t);
if (r) return r;
else return p;
}
else /* p->k > k */
p = p->l;
}
return NULL; /* k < everything in subtree */
}
/* find greatest point in t <= k */
rb_node *rb_tree_find_le(rb_tree *t, rb_key k)
{
return find_le(t->root, k, t);
}