数据结构算法中的关于二叉树的一些实验，该小程序主要实现了一个二叉树的前序，中序和后序表达式，同时还可以输入前序和中序来输出后序的内容。-Data structure binary tree algorithm on a number of experiments, the applet implements a binary tree of the main sequence before, in order and the order of expression, but also can e