构建二叉树结构进行四则运算。在控制台程序中输入书写习惯的表达式（可以包含括号），程序首先遍历提取运算符号，分辨优先级，然后构造二叉树，对二叉树后序遍历，运算得到结果。 输出运算结果和遍历顺序。-Construction of the structure of four binary arithmetic. Enter the writing habits of expression in the console program (may contain parentheses), the program first traversal extraction operation symbol, the resolution priority, and then construct a binary tree, after traversing Binary Tree, the calculation result. Output of the operational results and the order of traversal.