用JAVA写的计算一段数学表达式的程序，所用的算法及各类数据结构在很多教程中都有介绍，但代码都是不完整的，一般都是缺少自动机来获取符号。所以现在把我写的发上来，希望于大家一起交流。-JAVA calculated using a mathematical expression written in the procedures used by the algorithm and all kinds of data structures are introduced in many tutoria