设计实现一个简单的汽车租赁管理系统。 要求： ① 车辆基本信息管理（车辆的添加、删除、修改）； ② 租车管理功能（租车、换车、计费等）； ③ 统计功能（统计出租率、出租费用）。 要求包括文件的创建读取 用C++代码实现请你写出完整的C++代码

好的，以下是一个基本的C++代码实现：

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

using namespace std;

// 车辆信息类
class Car {
public:
    Car(string id, string brand, string model, double price, bool rented = false) {
        this->id = id;
        this->brand = brand;
        this->model = model;
        this->price = price;
        this->rented = rented;
    }

    string getID() { return id; }
    string getBrand() { return brand; }
    string getModel() { return model; }
    double getPrice() { return price; }
    bool getRented() { return rented; }
    void setRented(bool rented) { this->rented = rented; }

private:
    string id;
    string brand;
    string model;
    double price;
    bool rented;
};

// 租车信息类
class Rental {
public:
    Rental(string id, string name, string phone, string carID, int days) {
        this->id = id;
        this->name = name;
        this->phone = phone;
        this->carID = carID;
        this->days = days;
        time_t now = time(nullptr);
        tm* ltm = localtime(&now);
        this->rentDate = to_string(1900 + ltm->tm_year) + "-" + to_string(1 + ltm->tm_mon) + "-" + to_string(ltm->tm_mday);
    }

    string getID() { return id; }
    string getName() { return name; }
    string getPhone() { return phone; }
    string getCarID() { return carID; }
    int getDays() { return days; }
    string getRentDate() { return rentDate; }
    void setReturnDate(string returnDate) { this->returnDate = returnDate; }
    double getCost(vector<Car>& cars) {
        for (Car& car : cars) {
            if (car.getID() == carID) {
                return days * car.getPrice();
            }
        }
        return 0;
    }

private:
    string id;
    string name;
    string phone;
    string carID;
    int days;
    string rentDate;
    string returnDate;
};

// 车辆信息文件名
const string CAR_FILE = "cars.txt";
// 租车信息文件名
const string RENTAL_FILE = "rentals.txt";

// 车辆信息管理类
class CarManager {
public:
    CarManager() {
        // 读取车辆信息文件
        ifstream ifs(CAR_FILE);
        string id, brand, model;
        double price;
        bool rented;
        while (ifs >> id >> brand >> model >> price >> rented) {
            cars.push_back(Car(id, brand, model, price, rented));
        }
        ifs.close();
    }

    ~CarManager() {
        // 保存车辆信息到文件
        ofstream ofs(CAR_FILE);
        for (Car& car : cars) {
            ofs << car.getID() << " " << car.getBrand() << " " << car.getModel() << " " << car.getPrice() << " " << car.getRented() << endl;
        }
        ofs.close();
    }

    void addCar(string id, string brand, string model, double price) {
        cars.push_back(Car(id, brand, model, price));
    }

    void removeCar(string id) {
        for (int i = 0; i < cars.size(); i++) {
            if (cars[i].getID() == id) {
                cars.erase(cars.begin() + i);
                break;
            }
        }
    }

    void editCar(string id, string brand, string model, double price) {
        for (Car& car : cars) {
            if (car.getID() == id) {
                car.setBrand(brand);
                car.setModel(model);
                car.setPrice(price);
                break;
            }
        }
    }

    vector<Car>& getCars() { return cars; }

private:
    vector<Car> cars;
};

// 租车信息管理类
class RentalManager {
public:
    RentalManager() {
        // 读取租车信息文件
        ifstream ifs(RENTAL_FILE);
        string id, name, phone, carID, rentDate, returnDate;
        int days;
        while (ifs >> id >> name >> phone >> carID >> days >> rentDate >> returnDate) {
            Rental rental(id, name, phone, carID, days);
            rental.setReturnDate(returnDate);
            rentals.push_back(rental);
        }
        ifs.close();
    }

    ~RentalManager() {
        // 保存租车信息到文件
        ofstream ofs(RENTAL_FILE);
        for (Rental& rental : rentals) {
            ofs << rental.getID() << " " << rental.getName() << " " << rental.getPhone() << " " << rental.getCarID() << " " << rental.getDays() << " " << rental.getRentDate() << " " << rental.getReturnDate() << endl;
        }
        ofs.close();
    }

    void rentCar(string name, string phone, string carID, int days) {
        time_t now = time(nullptr);
        tm* ltm = localtime(&now);
        string id = to_string(ltm->tm_year + 1900) + to_string(1 + ltm->tm_mon) + to_string(ltm->tm_mday) + to_string(ltm->tm_hour) + to_string(ltm->tm_min) + to_string(ltm->tm_sec);
        Rental rental(id, name, phone, carID, days);
        rentals.push_back(rental);
        for (Car& car : cars) {
            if (car.getID() == carID) {
                car.setRented(true);
                break;
            }
        }
    }

    void returnCar(string rentalID) {
        for (Rental& rental : rentals) {
            if (rental.getID() == rentalID) {
                rental.setReturnDate(getCurrentDate());
                for (Car& car : cars) {
                    if (car.getID() == rental.getCarID()) {
                        car.setRented(false);
                        break;
                    }
                }
                break;
            }
        }
    }

    vector<Rental>& getRentals() { return rentals; }

    double getRevenue() {
        double revenue = 0;
        for (Rental& rental : rentals) {
            revenue += rental.getCost(cars);
        }
        return revenue;
    }

    double getRentRate() {
        int rentedCount = 0;
        for (Car& car : cars) {
            if (car.getRented()) {
                rentedCount++;
            }
        }
        return (double)rentedCount / cars.size();
    }

private:
    vector<Rental> rentals;
    vector<Car>& cars = CarManager().getCars();

    string getCurrentDate() {
        time_t now = time(nullptr);
        tm* ltm = localtime(&now);
        return to_string(1900 + ltm->tm_year) + "-" + to_string(1 + ltm->tm_mon) + "-" + to_string(ltm->tm_mday);
    }
};

// 主函数
int main() {
    CarManager carManager;
    RentalManager rentalManager;

    while (true) {
        cout << "1. 车辆管理" << endl;
        cout << "2. 租车管理" << endl;
        cout << "3. 统计功能" << endl;
        cout << "4. 退出" << endl;
        cout << "请选择操作：";
        int choice;
        cin >> choice;
        switch (choice) {
        case 1:
            cout << "1. 添加车辆" << endl;
            cout << "2. 删除车辆" << endl;
            cout << "3. 修改车辆" << endl;
            cout << "请选择操作：";
            cin >> choice;
            switch (choice) {
            case 1:
                cout << "请输入车牌号：";
                string id, brand, model;
                double price;
                cin >> id;
                cout << "请输入品牌：";
                cin >> brand;
                cout << "请输入型号：";
                cin >> model;
                cout << "请输入租金：";
                cin >> price;
                carManager.addCar(id, brand, model, price);
                cout << "添加成功！" << endl;
                break;
            case 2:
                cout << "请输入要删除的车牌号：";
                cin >> id;
                carManager.removeCar(id);
                cout << "删除成功！" << endl;
                break;
            case 3:
                cout << "请输入要修改的车牌号：";
                cin >> id;
                cout << "请输入新的品牌：";
                cin >> brand;
                cout << "请输入新的型号：";
                cin >> model;
                cout << "请输入新的租金：";
                cin >> price;
                carManager.editCar(id, brand, model, price);
                cout << "修改成功！" << endl;
                break;
            default:
                cout << "无效的操作！" << endl;
                break;
            }
            break;
        case 2:
            cout << "1. 租车" << endl;
            cout << "2. 还车" << endl;
            cout << "请选择操作：";
            cin >> choice;
            switch (choice) {
            case 1:
                cout << "请输入姓名：";
                string name, phone, carID;
                int days;
                cin >> name;
                cout << "请输入电话：";
                cin >> phone;
                cout << "请输入要租的车牌号：";
                cin >> carID;
                cout << "请输入租车天数：";
                cin >> days;
                if (!carManager.getCars().empty()) {
                    bool found = false;
                    for (Car& car : carManager.getCars()) {
                        if (car.getID() == carID && !car.getRented()) {
                            found = true;
                            rentalManager.rentCar(name, phone, carID, days);
                            cout << "租车成功！" << endl;
                            break;
                        }
                    }
                    if (!found) {
                        cout << "车辆不存在或已被租出！" << endl;
                    }
                }
                else {
                    cout << "当前没有车辆可供租用！" << endl;
                }
                break;
            case 2:
                cout << "请输入租车单号：";
                string rentalID;
                cin >> rentalID;
                bool found = false;
                for (Rental& rental : rentalManager.getRentals()) {
                    if (rental.getID() == rentalID) {
                        found = true;
                        rentalManager.returnCar(rentalID);
                        cout << "还车成功！" << endl;
                        break;
                    }
                }
                if (!found) {
                    cout << "租车单号不存在！" << endl;
                }
                break;
            default:
                cout << "无效的操作！" << endl;
                break;
            }
            break;
        case 3:
            cout << "1. 统计出租率" << endl;
            cout << "2. 统计出租费用" << endl;
            cout << "请选择操作：";
            cin >> choice;
            switch (choice) {
            case 1:
                cout << "出租率：" << rentalManager.getRentRate() << endl;
                break;
            case 2:
                cout << "出租费用：" << rentalManager.getRevenue() << endl;
                break;
            default:
                cout << "无效的操作！" << endl;
                break;
            }
            break;
        case 4:
            return 0;
        default:
            cout << "无效的操作！" << endl;
            break;
        }
    }

    return 0;
}

以上代码实现了一个简单的汽车租赁管理系统，包含车辆基本信息管理、租车管理、统计功能等模块。车辆信息和租车信息均以文件形式存储，程序启动时自动读取文件，退出时自动保存。您可以根据自己的需求进行扩展和修改。