说明：  用二叉链表存储二叉树，用“扩张先序遍历序列”创建二叉链表，对二叉树进行前、中、后序的遍历以及层次遍历，输出度为0、1、2的节点及节点数，线索化二叉树，根据线索化的二叉树查找二叉树中任意节点的前驱、后继，通过线索二叉树进行二叉树节点的删除、插入，以及按树状打印二叉树。
(Used to store binary tree binary tree, use the " expansion preorder sequence" to create the binary tree, the front of the binary tree, in traversing and traverse the level, the output of the sequence of the nodes and nodes 0,1,2 clues binary tree, binary tree to find clues of any node in binary precursor, successor, delete the binary tree node through clues tree, insert, and printed by the binary tree.)