一个学生成绩管理系统，有输入、输出、按平均分排序，按学号查找，插入、删除、输入统计信息，保存到文件退出功能，适宜c语言除学习者参考练习-A student achievement management system with input, output, divided by the average sorted by student number to find, insert, delete, enter the statistical information, save to a file