管理菜单：

1] 建立成绩单

2] 查询某一成绩

3] 求全班同学的平均分

4] 将成绩从小到大进行排序

5] 输出所有学生的成绩

6] 求全班成绩的最高分

7] 退出菜单-Management menu: 1] the establishment of transcr ipts 2] query results in a 3] for the whole class' s average score 4] the results are sorted from small to large 5] the output results of all students 6] for the highest achievement in his class at 7] from the menu