有5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，将原有数据和计算出的平均分数存放在磁盘文件stud中。

-5 students, each student will have three classes of results, data from the keyboard or above (including student number, name, class 3 results) to calculate the grade point average, the original data and the calculated average scores stored in the stud in the disk file. _8g P [u# M u0