实现电话簿管理程序， Mytel类描述单个电话号码，TelManager类负责管理电话号码。把增、删、改、查功能封装到该类中。要求电话号码能从磁盘读写。 用C++编写该程序

以下是实现电话簿管理程序的代码：

#include <iostream>
#include <fstream>
#include <string>
#include <vector>

using namespace std;

// Mytel类描述单个电话号码
class Mytel {
public:
    Mytel() {}
    Mytel(string name, string phone) : name(name), phone(phone) {}

    string getName() const { return name; }
    string getPhone() const { return phone; }

    void setName(string name) { this->name = name; }
    void setPhone(string phone) { this->phone = phone; }

    // 从文件中读取电话号码
    void read(ifstream& infile) {
        infile >> name >> phone;
    }

    // 将电话号码写入文件
    void write(ofstream& outfile) {
        outfile << name << " " << phone << endl;
    }

private:
    string name;
    string phone;
};

// TelManager类负责管理电话号码
class TelManager {
public:
    // 从文件中读取电话号码列表
    void load(string filename) {
        ifstream infile(filename);
        if (!infile) {
            cerr << "Error: Could not open file " << filename << endl;
            return;
        }
        Mytel mytel;
        while (infile) {
            mytel.read(infile);
            if (infile) {
                mytels.push_back(mytel);
            }
        }
        infile.close();
    }

    // 将电话号码列表写入文件
    void save(string filename) {
        ofstream outfile(filename);
        for (int i = 0; i < mytels.size(); i++) {
            mytels[i].write(outfile);
        }
        outfile.close();
    }

    // 增加电话号码
    void add(string name, string phone) {
        Mytel mytel(name, phone);
        mytels.push_back(mytel);
    }

    // 删除电话号码
    void remove(string name) {
        for (int i = 0; i < mytels.size(); i++) {
            if (mytels[i].getName() == name) {
                mytels.erase(mytels.begin() + i);
                break;
            }
        }
    }

    // 修改电话号码
    void update(string name, string phone) {
        for (int i = 0; i < mytels.size(); i++) {
            if (mytels[i].getName() == name) {
                mytels[i].setPhone(phone);
                break;
            }
        }
    }

    // 查找电话号码
    string search(string name) {
        for (int i = 0; i < mytels.size(); i++) {
            if (mytels[i].getName() == name) {
                return mytels[i].getPhone();
            }
        }
        return "Not found";
    }

private:
    vector<Mytel> mytels;
};

int main() {
    TelManager telmanager;
    telmanager.load("mytels.txt");

    while (true) {
        cout << "1. Add a phone number" << endl;
        cout << "2. Remove a phone number" << endl;
        cout << "3. Update a phone number" << endl;
        cout << "4. Search for a phone number" << endl;
        cout << "5. Save phone numbers" << endl;
        cout << "6. Quit" << endl;

        int choice;
        cout << "Enter your choice (1-6): ";
        cin >> choice;

        if (choice == 1) {
            string name, phone;
            cout << "Enter name: ";
            cin >> name;
            cout << "Enter phone number: ";
            cin >> phone;
            telmanager.add(name, phone);
            cout << "Phone number added successfully." << endl;
        }
        else if (choice == 2) {
            string name;
            cout << "Enter name: ";
            cin >> name;
            telmanager.remove(name);
            cout << "Phone number removed successfully." << endl;
        }
        else if (choice == 3) {
            string name, phone;
            cout << "Enter name: ";
            cin >> name;
            cout << "Enter new phone number: ";
            cin >> phone;
            telmanager.update(name, phone);
            cout << "Phone number updated successfully." << endl;
        }
        else if (choice == 4) {
            string name;
            cout << "Enter name: ";
            cin >> name;
            string phone = telmanager.search(name);
            cout << "Phone number: " << phone << endl;
        }
        else if (choice == 5) {
            telmanager.save("mytels.txt");
            cout << "Phone numbers saved successfully." << endl;
        }
        else if (choice == 6) {
            break;
        }
        else {
            cout << "Invalid choice. Please try again." << endl;
        }
    }

    return 0;
}

以上代码中，Mytel类描述单个电话号码，包括名字和电话号码。TelManager类负责管理电话号码，包括从文件中读取电话号码列表、将电话号码列表写入文件、增加电话号码、删除电话号码、修改电话号码、查找电话号码等功能。程序通过菜单方式提供增、删、改、查功能，同时能够将电话号码列表存储到磁盘中。