逆波兰算法，用以实现四则混合运算，可以支持加，减，乘，除，括号的优先级判断，得到运算结果。-RPN algorithm to achieve four hybrid operation, to support add, subtract, multiply, divide, to determine the priority of parentheses to get the results of operations.

逆波兰算法的实现算法，已经用类封装，专门用于计算逆波兰表达式，稍加修改可以增加更多运算方法。-Reverse Polish Algorithm algorithm, has been with the class package, specifically used to calculate the Reverse Polish Notation, slightly modified to add more computing methods.

中缀式变后缀式的代码。经典逆波兰式算法。-Reverse Polish notation