数据结构课程的实验。构造二叉搜索树，构造平衡二叉树-用AVL树实现，可以用两种树比较调平的过程，有插入节点、删出结点、调平、缩格打印树等功能。-Data structures course experiment. Construct a binary search tree, balanced binary tree structure- achieved with the AVL tree, the tree can be compared in two leveling process, t