程序介绍：对树的一些常用操作进行了封装，包括查询，插入，删除，遍历二叉树（中序，后序，前序） 以及以树的方式显示二对树的各个结点。-Program Descr iption: The tree of some common operations of the package, including the query, insert, delete, traversing a binary tree (in order, postorder, preorder), and the tree dis