（1）先输入第一组操作数，并将其存放在一个文件中。

（2）然后输入第二组操作数，并将其存放在第二个文件中。

（3）选择一种加减乘除运算。

（4）从第一个文件中取第一个操作数，从第二个文件中取第二个操作数，将其按照第三步中选择的运算做加减乘除后存入到第三个文件中。

（5）从第三个文件中读取出运算结果。-(A) to enter the first set of operands, and store it in a file. (2) and then enter the second operand, and stores it in the second file. (3) Select a subtraction multiplication and division. (4) from the first file in the first operand fetch from the second file, the second operand fetch, be selected in accordance with the third step in doing arithmetic operations to a third deposited after files. (5) from the file read out in the third operation result.