学生信息简易处理系统。当文件“student.dat”存在时，从文件中将学生信息读入内存，然后分别按照学号、成绩排序输出学生信息后退出；2)　　当文件不存在时，接受用户输入若干个学生的信息，然后将其存到“student.dat”文件中退出。-Student Information Easy System. When the file " student.dat"　exists, the student information from the file will be read into memory, and then were in accordance with the school, student achievement sort the output message and exit　2) when the file does not exist, a number that accepts user input student information , and then saved to " student.dat"　document exit.