有五个学生，每个学生有3门课的成绩，从键盘输入以上数据（包括学生号，姓名，三门课成绩），计算出平均成绩，况原有的数据和计算出的平均分数存放在磁盘文件"stud"中。-Five students, each student has three class results, input from the keyboard above the data (including student number, name, score three classes), calculate the average grade, the status of the original data and the calculated average storage In the disk file " stud"　in the.