(1) 设置运算符栈和操作数栈辅助分析算符优先关系；

(2) 在读入字符序列时，完成运算符和操作数的处理，以及相应运算；

(3) 在识别处运算数的同时，要将其字符序列形式转化成 float 型数据形式；

(4) 输入的字符序列中，操作数不一定是一位数，可能是多位数，如 16+32 ；

(6) 在程序中会用到两类栈：操作数栈和运算符栈，分别为 float 型数据和字符型数据，

思考在同一个程序中如何处理两类不同的数据类型？

-(1) set operator operand stack stack and operator precedence relations aided analysis　(2) a sequence of characters in the reading, the completion of operator and operand processing, and the corresponding operation　(3) In computing the number of identification at the same time , to form the character sequence into a float type data form　(4) Enter the character sequence, the operand is not necessarily a number, may be more digits, such as 16+32　(6) in the program will use two stacks: the operand stack and the operator stack, respectively, float-type data and character data, thinking in the same program, how to deal with two different data types?