题目：有5个学生，每个学生有3门课程的成绩，从键盘输入学生数据（包括学号，姓名，3门课程成绩），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。读入stud文件的内容，按平均分进行排序处理，将已排序的学生数据存入一个新文件“stud_sort”中。-Title: There are five students, there are three courses each student achievements, student data from the keyboard input (including the student number, name, 3 course grade), calculate the average score, the original data and calculated the average scores stored in the disk file " stud"　in the. Stud read the contents of the file, sort by average processing student data will be sorted into a new file " stud_sort"　in.