功能： （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。 其他要求： （1）要求处理double型或float型数据。 （2）能够处理程序运行结果中的各种异常-Functions: (1) first enter the first set of operands, and store it in a file. (2) and then enter the number of operations of the group of second, and it is stored in the second files. (3) choose a add, subtract, multiply and divide operations. (4) take the first operand　the first file,　the second documents　the second operand, the third step in accordance with the add, subtract, multiply and divide operations into third files. (5) read the results　the third files. Other requirements: (1) processing type double or float data. (2) to deal with the abnormal results of the program running results