我写的Java学生成绩管理系统源代码

我写的Java学生成绩管理系统源代码(6)             case 5: {
                print();//5.把数据全部打印到屏幕
                timeOut(2);
            }break;
            case 6: {
                lp.numSort();//6.把成绩按学号排序
                System.out.println("按照学号从小到大排序成功!\n"+
                "排序后:\n");
                print();
                timeOut(2);
            }break;
            case 7: {
                lp.rewrite();//7.修改数据
                timeOut(2);
            }break;
            case 8: {
                int count = lp.count();
                System.out.println("共有"+count+"个学生已经记录.");
                timeOut(2);
            }break;