C++習題與解析(繼承和派生-02)

6.6 編寫一個程序設計一個汽車類vehicle，包含的數(shù)據(jù)成員有車輪個數(shù)wheels和車重weight。小車類car是它的私有派生類其中包含載人數(shù)passenger_load?？ㄜ囶恡ruck是vehicle的私有派生類其中包含載人數(shù)passenger_load和載重量payload，每個類都有相關數(shù)據(jù)的輸出方法。
    解：
    vehicle類是基類由它派生出car類和truck類將公共的屬性和方法放在vehicle類中。
    本題程序如下：
    本程序的執(zhí)行結果如下：
    #include
    class vehicle // 定義汽車類
    {
    protected:
    int wheels; // 車輪數(shù)
    float weight; // 重量
    public:
    vehicle(int wheels,float weight);
    int get_wheels();
    float get_weight();
    float wheel_load();
    void show();
    };
    class car:public vehicle // 定義小車類
    {
    int passenger_load; // 載人數(shù)
    public:
    car(int wheels,float weight,int passengers=4);
    int get_passengers();
    void show();
    };
    class truck:public vehicle // 定義卡車類
    {
    int passenger_load; // 載人數(shù)
    float payload; // 載重量
    public:
    truck(int wheels,float weight,int passengers=2,float max_load=24000.00);
    int get_passengers();
    float efficiency();
    void show();
    };
    vehicle::vehicle(int wheels,float weight)
    {
    vehicle::wheels=wheels;
    vehicle::weight=weight;
    }
    int vehicle::get_wheels()
    {
    return wheels;
    }
    float vehicle::get_weight()
    {
    return weight/wheels;
    }
    void vehicle::show()
    {
    cout << "車輪:" << wheels << "個" << endl;
    cout << "重量:" << weight << "公斤" << endl;
    }
    car::car(int wheels, float weight,
    int passengers) :vehicle (wheels, weight)
    {
    passenger_load=passengers;
    }
    int car::get_passengers ()
    {
    return passenger_load;
    }
    void car::show()
    {
    cout <<" 車型:小車" << endl;
    vehicle::show();
    cout << "載人:" << passenger_load << "人" << endl;
    cout << endl;
    }
    truck:: truck(int wheels, float weight,int passengers, float max_load):vehicle(wheels,weight)
    {
    passenger_load=passengers;
    payload=max_load;
    }
    int truck::get_passengers()
    {
    return passenger_load;
    }
    float truck::efficiency()
    {
    return payload/(payload+weight);
    }
    void truck::show()
    {
    cout <<"車型:卡車" << endl;
    vehicle:: show ();
    cout << "載人:" << passenger_load << "人" << endl;
    cout << "效率:" << efficiency() << endl;
    cout << endl;
    }
    void main ()
    {
    car car1(4,2000,5);
    truck tru1(10,8000,3,340000);
    cout << "輸出結果" << endl;
    car1. show ();
    tru1. show ();
    }
    輸出結果
    車型：小車
    車輪：4個
    重量：2000公斤
    載人：5人
    車型：卡車
    車輪：10個
    重量：8000公斤
    載人：3人
    效率：0．977012