增强二叉搜索树是二叉搜索树的一种推广，其中每个结点除了保存关键字外，还保存了 以该结点为根的子树的结点数目（包括该结点本身）。通常我们使用链式结构来存储二叉搜索树。在本实验中， 我们要求使用链式结构实现增强二叉搜索树，并实现其建立、复制、前/中/后序遍历、层高统计、结构从属判断等操作。-Enhanced binary search tree is a generalization of a binary search tree, where each node except to save the keyword, but also save the node number points to the node is the root of the subtree (including the node itself). Usually we use the chain structure to store binary search tree. In this experiment, we require the use of chain structure to achieve enhanced binary search tree, and achieve its set up, copy, before/during/after the preorder, statistics storey structure subordinate judges and other operations.