1、可打印学生的信息；
2、可计算每个学生的M门功课的总成绩和平均成绩；
3、选择法按总成绩由高到低排序；
4、顺序查找法按学号查找；
5、可按姓名和学号分别查找；
6、有菜单功能；(1. Print student information;
2, calculate the total score and average grade of each student's M homework;
3, the selection method, according to the total score from high to low order;
4, using the order method to find, according to student number to find;
5, according to the name and student number, respectively;
6, menu function;)