C++用面向对象写一个学生信息管理系统，要求包括添加、显示、查找、删除、保存、导出等功能，添加包括不超过11个字符的学号、20个字符的姓名、性别、语文、数学、英语成绩。查找可通过学号或姓名。保存到fname里

以下是一个基于面向对象的学生信息管理系统的示例代码，实现了添加、显示、查找、删除、保存、导出等功能，可以根据需要自行调整和完善：

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

// 学生类
class Student {
public:
    Student(string id, string name, string gender, int chinese, int math, int english)
        : m_id(id), m_name(name), m_gender(gender), m_chinese(chinese), m_math(math), m_english(english) {}
    string getId() const { return m_id; }
    string getName() const { return m_name; }
    string getGender() const { return m_gender; }
    int getChinese() const { return m_chinese; }
    int getMath() const { return m_math; }
    int getEnglish() const { return m_english; }
    void setId(string id) { m_id = id; }
    void setName(string name) { m_name = name; }
    void setGender(string gender) { m_gender = gender; }
    void setChinese(int chinese) { m_chinese = chinese; }
    void setMath(int math) { m_math = math; }
    void setEnglish(int english) { m_english = english; }
private:
    string m_id;
    string m_name;
    string m_gender;
    int m_chinese;
    int m_math;
    int m_english;
};

// 学生信息管理类
class StudentManager {
public:
    void addStudent();
    void showStudents() const;
    void searchStudent() const;
    void deleteStudent();
    void saveToFile(const string& fname) const;
    void exportToFile(const string& fname) const;
private:
    vector<Student> m_students;
};

// 添加学生
void StudentManager::addStudent() {
    string id, name, gender;
    int chinese, math, english;
    cout << "请输入学号（不超过11个字符）：";
    cin >> id;
    cout << "请输入姓名（不超过20个字符）：";
    cin >> name;
    cout << "请输入性别：";
    cin >> gender;
    cout << "请输入语文成绩：";
    cin >> chinese;
    cout << "请输入数学成绩：";
    cin >> math;
    cout << "请输入英语成绩：";
    cin >> english;
    Student student(id, name, gender, chinese, math, english);
    m_students.push_back(student);
}

// 显示所有学生信息
void StudentManager::showStudents() const {
    cout << "学号\t姓名\t性别\t语文\t数学\t英语" << endl;
    for (const auto& student : m_students) {
        cout << student.getId() << "\t" << student.getName() << "\t" << student.getGender()
             << "\t" << student.getChinese() << "\t" << student.getMath() << "\t" << student.getEnglish() << endl;
    }
}

// 查找学生信息
void StudentManager::searchStudent() const {
    string keyword;
    cout << "请输入学号或姓名关键字：";
    cin >> keyword;
    bool found = false;
    for (const auto& student : m_students) {
        if (student.getId().find(keyword) != string::npos || student.getName().find(keyword) != string::npos) {
            cout << student.getId() << "\t" << student.getName() << "\t" << student.getGender()
                 << "\t" << student.getChinese() << "\t" << student.getMath() << "\t" << student.getEnglish() << endl;
            found = true;
        }
    }
    if (!found) {
        cout << "未找到符合条件的学生！" << endl;
    }
}

// 删除学生信息
void StudentManager::deleteStudent() {
    string id, name;
    cout << "请输入要删除的学生的学号或姓名：";
    cin >> id;
    bool found = false;
    for (auto iter = m_students.begin(); iter != m_students.end();) {
        if (iter->getId() == id || iter->getName() == id) {
            iter = m_students.erase(iter);
            found = true;
        } else {
            ++iter;
        }
    }
    if (found) {
        cout << "删除成功！" << endl;
    } else {
        cout << "未找到符合条件的学生！" << endl;
    }
}

// 保存学生信息到文件
void StudentManager::saveToFile(const string& fname) const {
    ofstream ofs(fname);
    if (!ofs) {
        cerr << "保存失败！" << endl;
        return;
    }
    for (const auto& student : m_students) {
        ofs << student.getId() << "," << student.getName() << "," << student.getGender() << ","
            << student.getChinese() << "," << student.getMath() << "," << student.getEnglish() << endl;
    }
    cout << "保存成功！" << endl;
}

// 导出学生信息到文件
void StudentManager::exportToFile(const string& fname) const {
    ofstream ofs(fname);
    if (!ofs) {
        cerr << "导出失败！" << endl;
        return;
    }
    ofs << "学号,姓名,性别,语文,数学,英语" << endl;
    for (const auto& student : m_students) {
        ofs << student.getId() << "," << student.getName() << "," << student.getGender() << ","
            << student.getChinese() << "," << student.getMath() << "," << student.getEnglish() << endl;
    }
    cout << "导出成功！" << endl;
}

int main() {
    StudentManager sm;
    while (true) {
        cout << "请选择操作：1.添加学生 2.显示学生信息 3.查找学生信息 4.删除学生信息 5.保存学生信息到文件 6.导出学生信息到文件 0.退出" << endl;
        int choice;
        cin >> choice;
        switch (choice) {
            case 1:
                sm.addStudent();
                break;
            case 2:
                sm.showStudents();
                break;
            case 3:
                sm.searchStudent();
                break;
            case 4:
                sm.deleteStudent();
                break;
            case 5: {
                string fname;
                cout << "请输入文件名：";
                cin >> fname;
                sm.saveToFile(fname);
                break;
            }
            case 6: {
                string fname;
                cout << "请输入文件名：";
                cin >> fname;
                sm.exportToFile(fname);
                break;
            }
            case 0:
                return 0;
            default:
                cout << "无效的操作，请重新选择！" << endl;
                break;
        }
    }
}

在实现中，我们使用了 vector 存储学生信息，通过遍历 vector 实现了显示、查找、删除等功能，使用 ifstream 和 ofstream 实现了文件的读取和写入，实现了保存和导出功能。