不使用SQL，必要时运用清屏等system指令，用c++实现以下主要功能： （1） 学生管理：对学生基本信息的增加、修改和删除 （2） 学生查询：对学生基本信息和成绩的查询 （3） 学生选课：用于学生选择课程学习 （4） 学生成绩：对学生各科成绩的添加、修改和删除等管理 （5） 打印：用来打印学生的基本信息和成绩 参考数据表： 学生（学号，姓名，性别，年级，出生年月，系号） 成绩（学号，成绩，课程号） 课程（课程号，课程名，学分，上课时间，选课人数）

这是一个比较复杂的项目，需要使用多个类和数据结构来实现。以下是一个简单的示例代码，供参考。

#include <iostream>
#include <vector>
#include <cstdlib> // 用于清屏操作

using namespace std;

// 定义学生类
class Student {
public:
    string id; // 学号
    string name; // 姓名
    string gender; // 性别
    int grade; // 年级
    string birthday; // 出生年月
    string departmentId; // 系号

    // 构造函数
    Student(string id, string name, string gender, int grade, string birthday, string departmentId) {
        this->id = id;
        this->name = name;
        this->gender = gender;
        this->grade = grade;
        this->birthday = birthday;
        this->departmentId = departmentId;
    }

    // 输出学生信息
    void printInfo() {
        cout << "学号：" << id << endl;
        cout << "姓名：" << name << endl;
        cout << "性别：" << gender << endl;
        cout << "年级：" << grade << endl;
        cout << "出生年月：" << birthday << endl;
        cout << "系号：" << departmentId << endl;
    }
};

// 定义成绩类
class Score {
public:
    string studentId; // 学号
    double score; // 成绩
    string courseId; // 课程号

    // 构造函数
    Score(string studentId, double score, string courseId) {
        this->studentId = studentId;
        this->score = score;
        this->courseId = courseId;
    }

    // 输出成绩信息
    void printInfo() {
        cout << "学号：" << studentId << endl;
        cout << "成绩：" << score << endl;
        cout << "课程号：" << courseId << endl;
    }
};

// 定义课程类
class Course {
public:
    string id; // 课程号
    string name; // 课程名
    int credit; // 学分
    string time; // 上课时间
    int numStudents; // 选课人数

    // 构造函数
    Course(string id, string name, int credit, string time) {
        this->id = id;
        this->name = name;
        this->credit = credit;
        this->time = time;
        this->numStudents = 0;
    }

    // 输出课程信息
    void printInfo() {
        cout << "课程号：" << id << endl;
        cout << "课程名：" << name << endl;
        cout << "学分：" << credit << endl;
        cout << "上课时间：" << time << endl;
        cout << "选课人数：" << numStudents << endl;
    }
};

// 定义学生管理类
class StudentManager {
private:
    vector<Student> students; // 存储学生信息的容器
    vector<Score> scores; // 存储成绩信息的容器

public:
    // 添加学生
    void addStudent(string id, string name, string gender, int grade, string birthday, string departmentId) {
        Student student(id, name, gender, grade, birthday, departmentId);
        students.push_back(student);
    }

    // 修改学生信息
    void modifyStudent(string id) {
        for (int i = 0; i < students.size(); i++) {
            if (students[i].id == id) {
                cout << "请输入修改后的信息：" << endl;
                cout << "学号：";
                cin >> students[i].id;
                cout << "姓名：";
                cin >> students[i].name;
                cout << "性别：";
                cin >> students[i].gender;
                cout << "年级：";
                cin >> students[i].grade;
                cout << "出生年月：";
                cin >> students[i].birthday;
                cout << "系号：";
                cin >> students[i].departmentId;
                cout << "修改成功！" << endl;
                return;
            }
        }
        cout << "未找到该学生！" << endl;
    }

    // 删除学生
    void deleteStudent(string id) {
        for (int i = 0; i < students.size(); i++) {
            if (students[i].id == id) {
                students.erase(students.begin() + i);
                cout << "删除成功！" << endl;
                return;
            }
        }
        cout << "未找到该学生！" << endl;
    }

    // 查询学生信息
    void queryStudent(string id) {
        for (int i = 0; i < students.size(); i++) {
            if (students[i].id == id) {
                students[i].printInfo();
                return;
            }
        }
        cout << "未找到该学生！" << endl;
    }

    // 添加成绩
    void addScore(string studentId, double score, string courseId) {
        Score scoreObj(studentId, score, courseId);
        scores.push_back(scoreObj);
    }

    // 修改成绩
    void modifyScore(string studentId, string courseId) {
        for (int i = 0; i < scores.size(); i++) {
            if (scores[i].studentId == studentId && scores[i].courseId == courseId) {
                cout << "请输入修改后的信息：" << endl;
                cout << "成绩：";
                cin >> scores[i].score;
                cout << "修改成功！" << endl;
                return;
            }
        }
        cout << "未找到该学生的该门课程成绩！" << endl;
    }

    // 删除成绩
    void deleteScore(string studentId, string courseId) {
        for (int i = 0; i < scores.size(); i++) {
            if (scores[i].studentId == studentId && scores[i].courseId == courseId) {
                scores.erase(scores.begin() + i);
                cout << "删除成功！" << endl;
                return;
            }
        }
        cout << "未找到该学生的该门课程成绩！" << endl;
    }

    // 查询学生所有成绩
    void queryScore(string studentId) {
        bool found = false;
        for (int i = 0; i < scores.size(); i++) {
            if (scores[i].studentId == studentId) {
                found = true;
                for (int j = 0; j < students.size(); j++) {
                    if (students[j].id == studentId) {
                        cout << "学生姓名：" << students[j].name << endl;
                        break;
                    }
                }
                scores[i].printInfo();
                cout << endl;
            }
        }
        if (!found) {
            cout << "未找到该学生的成绩！" << endl;
        }
    }

    // 选课
    void selectCourse(string studentId, string courseId) {
        bool found = false;
        for (int i = 0; i < scores.size(); i++) {
            if (scores[i].studentId == studentId && scores[i].courseId == courseId) {
                found = true;
                cout << "你已经选过该门课程！" << endl;
                break;
            }
        }
        if (!found) {
            for (int i = 0; i < courses.size(); i++) {
                if (courses[i].id == courseId) {
                    if (courses[i].numStudents >= 100) {
                        cout << "该门课程已满员，无法选课！" << endl;
                        break;
                    }
                    courses[i].numStudents++;
                    addScore(studentId, 0, courseId);
                    cout << "选课成功！" << endl;
                    break;
                }
            }
        }
    }

    // 输出所有学生信息
    void printAllStudents() {
        for (int i = 0; i < students.size(); i++) {
            students[i].printInfo();
            cout << endl;
        }
    }

    // 输出所有课程信息
    void printAllCourses() {
        for (int i = 0; i < courses.size(); i++) {
            courses[i].printInfo();
            cout << endl;
        }
    }

private:
    vector<Course> courses = { // 存储课程信息的容器
        Course("001", "语文", 3, "周一上午"),
        Course("002", "数学", 4, "周二上午"),
        Course("003", "英语", 2, "周三下午"),
        Course("004", "物理", 3, "周四上午"),
        Course("005", "化学", 3, "周五下午")
    };
};

// 主函数
int main() {
    StudentManager manager;

    while (true) {
        cout << "请选择操作：" << endl;
        cout << "1. 添加学生" << endl;
        cout << "2. 修改学生信息" << endl;
        cout << "3. 删除学生" << endl;
        cout << "4. 查询学生信息" << endl;
        cout << "5. 添加成绩" << endl;
        cout << "6. 修改成绩" << endl;
        cout << "7. 删除成绩" << endl;
        cout << "8. 查询学生所有成绩" << endl;
        cout << "9. 选课" << endl;
        cout << "10. 输出所有学生信息" << endl;
        cout << "11. 输出所有课程信息" << endl;
        cout << "0. 退出程序" << endl;

        int choice;
        cin >> choice;

        switch (choice) {
        case 1: { // 添加学生
            cout << "请输入学生信息：" << endl;
            string id, name, gender, birthday, departmentId;
            int grade;
            cout << "学号：";
            cin >> id;
            cout << "姓名：";
            cin >> name;
            cout << "性别：";
            cin >> gender;
            cout << "年级：";
            cin >> grade;
            cout << "出生年月：";
            cin >> birthday;
            cout << "系号：";
            cin >> departmentId;
            manager.addStudent(id, name, gender, grade, birthday, departmentId);
            cout << "添加成功！" << endl;
            break;
        }
        case 2: { // 修改学生信息
            cout << "请输入要修改的学生学号：";
            string id;
            cin >> id;
            manager.modifyStudent(id);
            break;
        }
        case 3: { // 删除学生
            cout << "请输入要删除的学生学号：";
            string id;
            cin >> id;
            manager.deleteStudent(id);
            break;
        }
        case 4: { // 查询学生信息
            cout << "请输入要查询的学生学号：";
            string id;
            cin >> id;
            manager.queryStudent(id);
            break;
        }
        case 5: { // 添加成绩
            cout << "请输入成绩信息：" << endl;
            string studentId, courseId;
            double score;
            cout << "学号：";
            cin >> studentId;
            cout << "课程号：";
            cin >> courseId;
            cout << "成绩：";
            cin >> score;
            manager.addScore(studentId, score, courseId);
            cout << "添加成功！" << endl;
            break;
        }
        case 6: { // 修改成绩
            cout << "请输入要修改的学生学号和课程号：";
            string studentId, courseId;
            cin >> studentId >> courseId;
            manager.modifyScore(studentId, courseId);
            break;
        }
        case 7: { // 删除成绩
            cout << "请输入要删除的学生学号和课程号：";
            string studentId, courseId;
            cin >> studentId >> courseId;
            manager.deleteScore(studentId, courseId);
            break;
        }
        case 8: { // 查询学生所有成绩
            cout << "请输入要查询的学生学号：";
            string id;
            cin >> id;
            manager.queryScore(id);
            break;
        }
        case 9: { // 选课
            cout << "请输入学生学号和课程号：";
            string studentId, courseId;
            cin >> studentId >> courseId;
            manager.selectCourse(studentId, courseId);
            break;
        }
        case 10: { // 输出所有学生信息
            manager.printAllStudents();
            break;
        }
        case 11: { // 输出所有课程信息
            manager.printAllCourses();
            break;
        }
        case 0: { // 退出程序
            return 0;
        }
        default: { // 输入错误
            cout << "输入错误，请重新输入！" << endl;
            break;
        }
        }

        system("pause"); // 暂停程序，等待用户按下任意键继续
        system("cls"); // 清屏
    }

    return 0;
}