按照书上介绍介绍的方法，模拟编译器计算表达式的方法，就是对栈的反复操作，具体算法见数据结构书。其中对运算符优先级确定上用到令一本书的算法。-In accordance with the method described in the book presented to simulate the calculation expression compiler method is repeated on the stack operation, the specific data structure