[数据结构]10.2实现binary search tree的查找和插入操作，用非递归的方法实现

//*****************************************************insert循环版**************************************template<class Record>Error_code Binary_search_tree<Record>::c_insert(const Record & item){Binary_node<Record> *current=root, *previous=root;if(!current)root = new Binary_node<Record>(item);else {while (current != NULL) {previous = current;if (current->data > item)current = current->left_child;else if (current->data < item)current = current->right_child;else return duplicate_error;}if (previous->data > item)previous->left_child = new Binary_node<Record>(item);elseprevious->right_child = new Binary_node<Record>(item);return success;}}//******************************************************remove循环版*************************************template<class Record>Error_code Binary_search_tree<Record>::c_remove(const Record & item){if (root == NULL || root->data == item)return destroy(root);else {Binary_node<Record> *current = root, *previous = root;while (current != NULL) {previous = current;if (current->data > item)current = current->left_child;else if (current->data < item)current = current->right_child;else return destroy(current);}return not_present;}}template<class Record>Error_code Binary_search_tree<Record>::destroy(Binary_node<Record>*& sub_root){if (sub_root == NULL)return not_present;Binary_node<Entry> *to_delete = sub_root;if (sub_root->left_child == NULL) sub_root = sub_root->right_child;else if (sub_root->right_child == NULL) sub_root = sub_root->left_child;else {to_delete = sub_root->left_child;Binary_node<Entry> *parent = sub_root;while (!to_delete->right_child) {parent = to_delete;to_delete = to_delete->right_child;}sub_root->data = to_delete->data;if (parent == sub_root)sub_root->left_child = to_delete->left_child;//Special condition:no right_child under to_deleteelse parent->right_child = to_delete->right_child;}delete to_delete;return success;