（1）从键盘上输入数据，建立二叉链表。

（2）前序遍历、中序遍历、后序遍历二叉树：递归算法。

（3）前序遍历、中序遍历、后序遍历二叉树：非递归算法。

（4）借助队列实现二叉树的层次遍历。

在主函数中设计一个简单的菜单，分别调试上述算法。-(1) input data　the keyboard, build binary list.

(2) former preorder, preorder, after preorder binary tree: recursive algorithm.

(3) the former preorder, preorder, after preorder binary tree: a non-recursive algorithm.

(4) With the queue binary tree hierarchy traversal.

Design a simple menu in the main function, namely debug the algorithm described above.