编写一个算法程序实现：

1、建立一棵6个结点的二叉树，结点的数据值是正整数，并按中序输出之；

2、完成对以上二叉树中所有结点的左、右子树相互交换，并按中序输出交换以后的结果。

3、统计二叉树叶子结点的个数，并输出结果。

-Write an algorithm Program: 1. Establish a tree node 6 binary data value node is a positive integer, the output of the press in order　2, complete binary tree above all nodes in the left and right subtree mutual exchange, according to the exchange after the results of the output sequence. 3, the number of binary tree leaf node statistics, and outputs the result.