procedure insert_child (P:node;E:elemtype); (This procedure is defined for constructing trees in a top-down manner. B A node containing element E will be created and it will be made the right-most child of node P*) procedure delete (var T:tree); B (This procedure deletes all the nodes of the tree T,and T will be made an empty tree.The tree T should not be a subtree of another tree * procedure assign(T1 tree;var T2:tree); (This procedure copies the entire tree T1 and asigns it to T2 * S/B 你能够从你的判断中得到一个一般 性的规律吗： 当你定义一个数据结构时，哪些操 作是必须的，哪些操作是特定的？B B S/B 你能够从你的判断中得到一个一般 性的规律吗： 当你定义一个数据结构时，哪些操 作是必须的，哪些操作是特定的？