将一个学生的3门课成绩文件进行插入处理，程序先计算插入学生的平均成绩，然后将它按照平均分的高低顺序插入。插入后建立一个新的文件。-Insert processing of a student' s course grades file inserted into the student' s grade point average, the program first calculated, and then insert it in accordance with the average high and low order. After insertion, create a new file.