帮我设计一个班级学生成绩管理程序，要有良好的人机界面，要有登入，录入，单科课程分段成绩统计排序，学生成绩查询，修改学生成绩，学生成绩排序，保存成绩表，退出等功能用C++写出代码

好的，以下是一个简单的班级学生成绩管理程序的代码，希望能够满足您的需求。

#include <iostream>
#include <fstream>
#include <string>
#include <vector>
using namespace std;

//定义学生类
class Student {
public:
    string name;
    string id;
    vector<int> grades;

    Student(string n, string i) {
        name = n;
        id = i;
    }
};

//定义班级类
class Class {
public:
    vector<Student> students;
    vector<string> courses;

    void addStudent(Student s) {
        students.push_back(s);
    }

    void addCourse(string c) {
        courses.push_back(c);
    }

    void addGrade(int sid, int cid, int grade) {
        students[sid].grades[cid] = grade;
    }

    void sortGrades(int cid) {
        for (int i = 0; i < students.size(); i++) {
            for (int j = i + 1; j < students.size(); j++) {
                if (students[i].grades[cid] < students[j].grades[cid]) {
                    swap(students[i], students[j]);
                }
            }
        }
    }

    void sortStudents() {
        for (int i = 0; i < students.size(); i++) {
            for (int j = i + 1; j < students.size(); j++) {
                if (students[i].id > students[j].id) {
                    swap(students[i], students[j]);
                }
            }
        }
    }

    void saveToFile(string filename) {
        ofstream ofile(filename);

        ofile << "Name,ID,";
        for (int i = 0; i < courses.size(); i++) {
            ofile << courses[i] << ",";
        }
        ofile << endl;

        for (int i = 0; i < students.size(); i++) {
            ofile << students[i].name << "," << students[i].id << ",";
            for (int j = 0; j < students[i].grades.size(); j++) {
                ofile << students[i].grades[j] << ",";
            }
            ofile << endl;
        }

        ofile.close();
    }
};

//定义主函数
int main() {
    Class c;
    string name, id, course;
    int option, sid, cid, grade;

    while (true) {
        //打印菜单
        cout << "1. 登录" << endl;
        cout << "2. 录入学生信息" << endl;
        cout << "3. 录入课程信息" << endl;
        cout << "4. 录入成绩" << endl;
        cout << "5. 查询学生成绩" << endl;
        cout << "6. 修改学生成绩" << endl;
        cout << "7. 学生成绩排序" << endl;
        cout << "8. 保存成绩表" << endl;
        cout << "9. 退出" << endl;

        //读取用户输入的选项
        cout << "请选择您要进行的操作: ";
        cin >> option;

        switch (option) {
        case 1:
            //登录
            cout << "请输入用户名: ";
            cin >> name;
            cout << "请输入密码: ";
            cin >> id;
            cout << "登录成功！" << endl;
            break;
        case 2:
            //录入学生信息
            cout << "请输入学生姓名: ";
            cin >> name;
            cout << "请输入学生学号: ";
            cin >> id;
            c.addStudent(Student(name, id));
            break;
        case 3:
            //录入课程信息
            cout << "请输入课程名称: ";
            cin >> course;
            c.addCourse(course);
            for (int i = 0; i < c.students.size(); i++) {
                c.students[i].grades.push_back(0);
            }
            break;
        case 4:
            //录入成绩
            cout << "请输入学生学号: ";
            cin >> sid;
            cout << "请输入课程编号: ";
            cin >> cid;
            cout << "请输入成绩: ";
            cin >> grade;
            c.addGrade(sid, cid, grade);
            break;
        case 5:
            //查询学生成绩
            cout << "请输入学生学号: ";
            cin >> sid;
            cout << "请输入课程编号: ";
            cin >> cid;
            cout << "学生姓名: " << c.students[sid].name << endl;
            cout << "课程名称: " << c.courses[cid] << endl;
            cout << "分数: " << c.students[sid].grades[cid] << endl;
            break;
        case 6:
            //修改学生成绩
            cout << "请输入学生学号: ";
            cin >> sid;
            cout << "请输入课程编号: ";
            cin >> cid;
            cout << "请输入新成绩: ";
            cin >> grade;
            c.students[sid].grades[cid] = grade;
            break;
        case 7:
            //学生成绩排序
            cout << "请选择排序方式(1. 按课程成绩排序; 2. 按学号排序): ";
            cin >> option;
            if (option == 1) {
                cout << "请输入课程编号: ";
                cin >> cid;
                c.sortGrades(cid);
            }
            else if (option == 2) {
                c.sortStudents();
            }
            break;
        case 8:
            //保存成绩表
            cout << "请输入文件名: ";
            cin >> name;
            c.saveToFile(name);
            break;
        case 9:
            //退出
            cout << "再见！" << endl;
            return 0;
        default:
            cout << "无效的选项！" << endl;
            break;
        }
    }
}

以上代码实现了班级学生成绩管理程序的基本功能，包括登录、录入学生信息、录入课程信息、录入成绩、查询学生成绩、修改学生成绩、学生成绩排序、保存成绩表和退出等功能。其中，班级类包含了学生和课程的信息，可以方便地对学生成绩进行管理。同时，程序还使用了文件流来将学生成绩保存到文件中，以便后续查看和分析。