请用c++编写这个代码

好的，以下是用C++编写的汽车租赁系统代码，根据题目要求使用了继承和多态的知识点：

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

class Vehicle {
public:
    virtual string getType() = 0;
    virtual string getBrand() = 0;
    virtual string getModel() = 0;
    virtual int getSeats() = 0;
    virtual int getRent() = 0;
};

class Car : public Vehicle {
private:
    string type = "Car";
    string brand;
    string model;
    int seats;
    int rent;
public:
    Car(string brand, string model, int seats, int rent) {
        this->brand = brand;
        this->model = model;
        this->seats = seats;
        this->rent = rent;
    }
    string getType() {
        return type;
    }
    string getBrand() {
        return brand;
    }
    string getModel() {
        return model;
    }
    int getSeats() {
        return seats;
    }
    int getRent() {
        return rent;
    }
};

class SUV : public Vehicle {
private:
    string type = "SUV";
    string brand;
    string model;
    int seats;
    int rent;
public:
    SUV(string brand, string model, int seats, int rent) {
        this->brand = brand;
        this->model = model;
        this->seats = seats;
        this->rent = rent;
    }
    string getType() {
        return type;
    }
    string getBrand() {
        return brand;
    }
    string getModel() {
        return model;
    }
    int getSeats() {
        return seats;
    }
    int getRent() {
        return rent;
    }
};

class Bus : public Vehicle {
private:
    string type = "Bus";
    string brand;
    string model;
    int seats;
    int rent;
public:
    Bus(string brand, string model, int seats, int rent) {
        this->brand = brand;
        this->model = model;
        this->seats = seats;
        this->rent = rent;
    }
    string getType() {
        return type;
    }
    string getBrand() {
        return brand;
    }
    string getModel() {
        return model;
    }
    int getSeats() {
        return seats;
    }
    int getRent() {
        return rent;
    }
};

int main() {
    int days;
    string vehicleType, brand, model;
    int seats, rent;

    cout << "Enter number of days rented: ";
    cin >> days;

    cout << "Enter vehicle type (car/suv/bus): ";
    cin >> vehicleType;

    if (vehicleType == "car") {
        cout << "Enter car brand: ";
        cin >> brand;
        cout << "Enter car model: ";
        cin >> model;
        cout << "Enter number of seats: ";
        cin >> seats;
        cout << "Enter daily rent: ";
        cin >> rent;
        Car car(brand, model, seats, rent);
        cout << car.getType() << " - " << car.getBrand() << " " << car.getModel() << " (" << car.getSeats() << " seats)" << endl;
        cout << "Rent per day: $" << car.getRent() << endl;
        cout << "Total rent: $" << car.getRent() * days << endl;
    } else if (vehicleType == "suv") {
        cout << "Enter SUV brand: ";
        cin >> brand;
        cout << "Enter SUV model: ";
        cin >> model;
        cout << "Enter number of seats: ";
        cin >> seats;
        cout << "Enter daily rent: ";
        cin >> rent;
        SUV suv(brand, model, seats, rent);
        cout << suv.getType() << " - " << suv.getBrand() << " " << suv.getModel() << " (" << suv.getSeats() << " seats)" << endl;
        cout << "Rent per day: $" << suv.getRent() << endl;
        cout << "Total rent: $" << suv.getRent() * days << endl;
    } else if (vehicleType == "bus") {
        cout << "Enter bus brand: ";
        cin >> brand;
        cout << "Enter bus model: ";
        cin >> model;
        cout << "Enter number of seats: ";
        cin >> seats;
        cout << "Enter daily rent: ";
        cin >> rent;
        Bus bus(brand, model, seats, rent);
        cout << bus.getType() << " - " << bus.getBrand() << " " << bus.getModel() << " (" << bus.getSeats() << " seats)" << endl;
        cout << "Rent per day: $" << bus.getRent() << endl;
        cout << "Total rent: $" << bus.getRent() * days << endl;
    } else {
        cout << "Invalid vehicle type!" << endl;
    }

    return 0;
}

在上述代码中，我们定义了一个基类 `Vehicle`，其中包含了汽车的类型、品牌、型号、座位数和租金信息等。然后，我们派生出了三个子类 `Car`、`SUV` 和 `Bus`，分别代表了小轿车、SUV 和客车。在每个子类中，我们实现了基类中定义的虚函数，以便获取各自的具体信息。在 `main` 函数中，我们根据用户的输入选择具体的车型，并创建相应的实例，输出车辆信息和租金信息等。

注意，在实现 `Vehicle` 类时，我们使用了纯虚函数，即 `virtual string getType() = 0;` 等，这是为了使得 `Vehicle` 类成为一个抽象类，只能用来作为其他类的基类而不能直接实例化。