一个有关二叉树的小程序，对二叉树的学习有用。利用非递归实现二叉树先序中序的遍历算法，程序中利用递归和交换函数实现了交换左右子树。-The binary tree is a small program useful for the study of the binary tree. Using the first order non-recursive binary tree traversal algorithm in the order the program and exchange the use of recursive functions is the exchange of left and right subtree.