이진탐색트리 검색 추가 삭제

TNode* search(TNode* n, int key) {
    if (n == NULL) return NULL;
    else if (key == n->data) return n;
    else if (key < n->data) return search(n->left, key);
    else return search(n->right, key);
}
int insert(TNode* r, TNode* n) {
    if (n->data == r->data) return 0;
    else if (n->data < r->data) {
        if (r->left == NULL) r->left = n;
        else insert(r->left, n);
    }
    else {
        if (r->right == NULL) r->right = n;
        else insert(r->right, n);
    }
    return 1;
}
void delete(TNode* parent, TNode* node) {
    TNode* child, * succ, * succp;
    // case 1
    if ((node->left == NULL && node->right == NULL)) {
        if (parent == NULL) root = NULL;
        else {
            if (parent->left == node) {
                parent->left = NULL;
            }
            else {
                parent->right = NULL;
            }
        }
    }
    // case 2
    else if (node->left == NULL || node->right == NULL) {
        child = (node->left != NULL) ? node->left : node->right;
        if (node == root) root = child;
        else {
            if (parent->left == node) {
                parent->left = child;
            }
            else {
                parent->right = child;
            }
        }
    }
    // case 3
    else {
        succp = node;
        succ = node->right;
        while (succ->left != NULL) {
            succp = succ;
            succ = succ->left;
        }
        if (succp->left == succ) {
            succp->left = succ->right;
        }
        else {
            succp->right = succ->right;
        }
        node->data = succ->data;
        node = succ;
    }
    free(node);

}