根据二叉树的抽象数据类型的定义，使用二叉链表实现一个二叉树。

二叉树的基本功能：

1、二叉树的建立

2、前序遍历二叉树

3、中序遍历二叉树

4、后序遍历二叉树

5、按层序遍历二叉树

6、求二叉树的深度

7、求指定结点到根的路径

8、二叉树的销毁

9、其他：自定义操作-According to a binary tree definition of abstract data types, use two forks to achieve a binary tree list. The basic functions of a binary tree: 1, the establishment of two binary tree, preorder traversal binary tree 3, 4 in order binary tree traversal, postorder binary tree 5, according to a binary tree traversal sequence 6, seeking binary tree of depth 7, find the specified node to the root of the path 8, the destruction of binary 9, Other: Custom Actions