利用堆栈实现计算器的功能，并把输入计算式表达成后缀表达式的形式-Use the calculator function stack implementation, and to enter into a form of expression formula postfix expressions

基于C++的计算器。先把所有数据和字符postfix输出再进行计算。内附queue和functions的packet。-Based C++ calculator. All data and character first and then calculated postfix output. Queue and functions included in the packet.