说明：  用链表实现学生成绩管理系统，实现插入，删除，新建，查找，修改等基本功能。并实现文件的输入和输出，退出系统时学生信息保存在一个文本文件中。进入系统时要求输入密码，该密码随机生成，运行后保存在文件目录的password.txt下。
(List with the realization of student achievement management system, the realization of insert, delete, new, find, modify the basic functionality. And the realization of paper input and output from the system when the student information stored in a text file. Into the system when asked to enter a password, the randomly generated password, run after the save in the document under password.txt directory.)