Calculator algorithm with postfix notation. Example of usage.

中缀表达式转后缀表达式，数据结构中堆栈的应用。-Switch to postfix infix notation expressions, the data structure stack applications.

This program takes an equation in prefix,infix, or postfix mode with proper parenthesis and parses the equation into a binary tree to show which equations come first, then outputs the same equation back in prefix,infix, and postfix notation.

课程作业, 将输入的前缀表达式转换为对应的逆波兰表达式(后缀表达式)-Course work, the prefix expression is converted to the corresponding input Reverse Polish Notation (postfix expression)