这是一个学生成绩管理系统，其中“I”表示插入，“L”表示浏览，“Q”表示查询，

“E”表示退出，“D”表示删除，“M”表示修改,\"c\"表示统计各分数段人数,\"p\"表示打印.

-This is a performance management system for students, "I" to insert said, "L" said View, "Q" said inquiries, "E" from "D" to delete said, "M" said the amendments "c" indicates a statistical fraction of the number of "p" said Print.