用C加加写学生信息管理系统

下面是一个简单的学生信息管理系统的示例代码，使用C++编写：

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

const int MAX_STUDENT_NUM = 100; // 最大学生数
const int MAX_NAME_LEN = 20; // 学生姓名最大长度

struct Student {
    string name;
    int age;
    float score;
};

int main() {
    Student students[MAX_STUDENT_NUM]; // 学生数组
    int studentNum = 0; // 学生数目
    char choice = ' '; // 菜单选择

    while (true) {
        // 显示菜单
        cout << "====================" << endl;
        cout << "1. 添加学生信息" << endl;
        cout << "2. 查询学生信息" << endl;
        cout << "3. 修改学生信息" << endl;
        cout << "4. 删除学生信息" << endl;
        cout << "5. 显示所有学生信息" << endl;
        cout << "6. 退出程序" << endl;
        cout << "====================" << endl;
        cout << "请选择: ";
        cin >> choice;

        switch (choice) {
            case '1': // 添加学生信息
                if (studentNum >= MAX_STUDENT_NUM) {
                    cout << "学生数目已达到最大值" << endl;
                } else {
                    Student newStudent;
                    cout << "请输入学生姓名: ";
                    cin >> newStudent.name;
                    cout << "请输入学生年龄: ";
                    cin >> newStudent.age;
                    cout << "请输入学生成绩: ";
                    cin >> newStudent.score;
                    students[studentNum] = newStudent;
                    studentNum++;
                    cout << "添加成功" << endl;
                }
                break;
            case '2': // 查询学生信息
                if (studentNum == 0) {
                    cout << "学生信息为空" << endl;
                } else {
                    string name;
                    cout << "请输入要查询的学生姓名: ";
                    cin >> name;
                    bool found = false;
                    for (int i = 0; i < studentNum; i++) {
                        if (students[i].name == name) {
                            cout << "姓名: " << students[i].name << endl;
                            cout << "年龄: " << students[i].age << endl;
                            cout << "成绩: " << students[i].score << endl;
                            found = true;
                            break;
                        }
                    }
                    if (!found) {
                        cout << "未找到该学生" << endl;
                    }
                }
                break;
            case '3': // 修改学生信息
                if (studentNum == 0) {
                    cout << "学生信息为空" << endl;
                } else {
                    string name;
                    cout << "请输入要修改的学生姓名: ";
                    cin >> name;
                    bool found = false;
                    for (int i = 0; i < studentNum; i++) {
                        if (students[i].name == name) {
                            cout << "请输入修改后的信息" << endl;
                            cout << "年龄: ";
                            cin >> students[i].age;
                            cout << "成绩: ";
                            cin >> students[i].score;
                            found = true;
                            cout << "修改成功" << endl;
                            break;
                        }
                    }
                    if (!found) {
                        cout << "未找到该学生" << endl;
                    }
                }
                break;
            case '4': // 删除学生信息
                if (studentNum == 0) {
                    cout << "学生信息为空" << endl;
                } else {
                    string name;
                    cout << "请输入要删除的学生姓名: ";
                    cin >> name;
                    bool found = false;
                    for (int i = 0; i < studentNum; i++) {
                        if (students[i].name == name) {
                            for (int j = i; j < studentNum - 1; j++) {
                                students[j] = students[j + 1];
                            }
                            studentNum--;
                            found = true;
                            cout << "删除成功" << endl;
                            break;
                        }
                    }
                    if (!found) {
                        cout << "未找到该学生" << endl;
                    }
                }
                break;
            case '5': // 显示所有学生信息
                if (studentNum == 0) {
                    cout << "学生信息为空" << endl;
                } else {
                    for (int i = 0; i < studentNum; i++) {
                        cout << "姓名: " << students[i].name << endl;
                        cout << "年龄: " << students[i].age << endl;
                        cout << "成绩: " << students[i].score << endl;
                        cout << "------------------" << endl;
                    }
                }
                break;
            case '6': // 退出程序
                cout << "程序已退出" << endl;
                return 0;
            default:
                cout << "无效的选择" << endl;
        }
    }

    return 0;
}

上述代码实现了一个简单的学生信息管理系统，可以通过菜单进行添加、查询、修改、删除和显示学生信息。在这个示例中，使用结构体存储每个学生的信息，并使用数组来存储所有学生的信息。当然，这只是一个简单的示例，实际情况下可能需要更加复杂的实现方式。