编写程序，设计一个汽车类Vehicle，包含的数据成员有车轮个数wheels和车重weight，带参数的构造函数、拷贝构造函数、数据成员设置函数Set()、数据成员显示函数show()。 小车类Car是vehicle的派生类其中包含载人数passenger_load。 卡车类Truck是vehicle的派生类其中包含载人数passenger_load和载重量payload。 每个类都有相关数据的输出方法，在主函数中创建各派生类对象，并调用个成员函数进行测试。

以下是程序代码：

#include <iostream>
using namespace std;

class Vehicle {
protected:
    int wheels;
    int weight;

public:
    Vehicle() {
        wheels = 0;
        weight = 0;
    }

    Vehicle(int w, int we) {
        wheels = w;
        weight = we;
    }

    Vehicle(const Vehicle &v) {
        wheels = v.wheels;
        weight = v.weight;
    }

    void Set(int w, int we) {
        wheels = w;
        weight = we;
    }

    void show() {
        cout << "Wheels: " << wheels << endl;
        cout << "Weight: " << weight << endl;
    }
};

class Car : public Vehicle {
protected:
    int passenger_load;

public:
    Car() {
        passenger_load = 0;
    }

    Car(int w, int we, int p) : Vehicle(w, we) {
        passenger_load = p;
    }

    Car(const Car &c) : Vehicle(c) {
        passenger_load = c.passenger_load;
    }

    void Set(int w, int we, int p) {
        Vehicle::Set(w, we);
        passenger_load = p;
    }

    void show() {
        Vehicle::show();
        cout << "Passenger Load: " << passenger_load << endl;
    }
};

class Truck : public Vehicle {
protected:
    int passenger_load;
    int payload;

public:
    Truck() {
        passenger_load = 0;
        payload = 0;
    }

    Truck(int w, int we, int p, int pl) : Vehicle(w, we) {
        passenger_load = p;
        payload = pl;
    }

    Truck(const Truck &t) : Vehicle(t) {
        passenger_load = t.passenger_load;
        payload = t.payload;
    }

    void Set(int w, int we, int p, int pl) {
        Vehicle::Set(w, we);
        passenger_load = p;
        payload = pl;
    }

    void show() {
        Vehicle::show();
        cout << "Passenger Load: " << passenger_load << endl;
        cout << "Payload: " << payload << endl;
    }
};

int main() {
    Vehicle v(4, 2000);
    v.show();

    Car c(4, 1500, 5);
    c.show();

    Truck t(8, 5000, 2, 10000);
    t.show();

    return 0;
}

程序输出：

Wheels: 4
Weight: 2000
Wheels: 4
Weight: 1500
Passenger Load: 5
Wheels: 8
Weight: 5000
Passenger Load: 2
Payload: 10000