C++多态的示例详解

class AbstractCalculator
{
public:
    //纯虚函数，用来得到计算结果
    virtual void getResult() = 0;
    float num1, num2;
};
//加法类
class Add :public AbstractCalculator
{
public:
    void getResult()
    {
        cout << num1 << "+" << num2 << "=" << num1 + num2 << endl;
    }
};
//减法类
class Sub :public AbstractCalculator
{
public:
    void getResult()
    {
        cout << num1 << "-" << num2 << "=" << num1 - num2 << endl;
    }
};
//乘法类
class Mul :public AbstractCalculator
{
public:
    void getResult()
    {
        cout << num1 << "*" << num2 << "=" << num1 * num2 << endl;
    }
};
//除法类
class Des :public AbstractCalculator
{
public:
    void getResult()
    {
        cout << num1 << "/" << num2 << "=" << num1 / num2 << endl;
    }
};
void main()
{
    //1、加法
    AbstractCalculator *abc = new Add();
    abc->num1 = 2.1;
    abc->num2 = 3.9;
    abc->getResult();
    delete abc;
    //2、减法
    abc = new Sub();
    abc->num1 = 3.9;
    abc->num2 = 2.1;
    abc->getResult();
    delete abc;
    //3、乘法
    abc = new Mul();
    abc->num1 = 4.2;
    abc->num2 = 2;
    abc->getResult();
    delete abc;
    //4、除法
    abc = new Des();
    abc->num1 = 8.8;
    abc->num2 = 2;
    abc->getResult();
    delete abc;
}

#include<iOStream>
using namespace std;
//使用多态制作奶茶
class AbstractDrink
{
public:
    //制作开水
    virtual void boiledWater() = 0;
    //冲泡
    virtual void brew() = 0;
    //倒入杯中
    virtual void inCup() = 0;
    //加入佐料
    virtual void pour() = 0;
    void makeDrink()
    {
        this->boiledWater();
        this->brew();
        this->inCup();
        this->pour();
    }
};
//制作咖啡
class Coffee :public AbstractDrink
{
public:
    //煮水
    virtual void boiledWater()
    {
        cout << "先把水煮开" << endl;
    }
    //冲泡 
    virtual void brew()
    {
        cout << "开始冲泡咖啡" << endl;
    }
    //倒入杯中
    virtual void inCup()
    {
        cout << "全部倒入杯中" << endl;
    }
    //加入辅料
    virtual void pour()
    {
        cout << "加入糖和牛奶" << endl;
        cout << "牛奶咖啡制作完成" << endl;
    }
};
//制作茶水
class Tea :public AbstractDrink
{
public:
    //煮水
    virtual void boiledWater()
    {
        cout << "先把水煮开" << endl;
    }
    //冲泡 
    virtual void brew()
    {
        cout << "开始冲泡茶叶" << endl;
    }
    //倒入杯中
    virtual void inCup()
    {
        cout << "全部倒入杯中" << endl;
    }
    //加入辅料
    virtual void pour()
    {
        cout << "加入枸杞" << endl;
        cout << "茶水制作完成" << endl;
    }
};
//制作函数
void DoWork(AbstractDrink* abs)//父类指针指向子类对象AbstractDrinking* abs = new Coffee;
{
    abs->makeDrink();
    delete abs;//手动释放
    //堆区的数据被销毁了但是指针的类型没变,可以多次利用
}
void test()
{
    DoWork(new Coffee);
    cout << "---------------------" << endl;
    DoWork(new Tea);
}
void main()
{
    test();
}

class CPU
{
public:
    virtual void calculate() = 0;
};
class VideoCard
{
public:
    virtual void display() = 0;
};
class Storage
{
public:
    virtual void storage() = 0;
};
class Computer
{
public:
    Computer(CPU* cpu, VideoCard* vc, Storage* sto)
    {
        m_cpu = cpu;
        m_vc = vc;
        m_sto = sto;
    }
    //提供一个工作的函数
    void work()
    {
        m_cpu->calculate();
        m_vc->display();
        m_sto->storage();
    }
    //提供析构函数释放3个电脑零件
    ~Computer()
    {
        //释放CPU零件
        if (m_cpu != NULL)
        {
            delete m_cpu;
            m_cpu = NULL;
        }
        //释放显卡零件
        if (m_vc != NULL)
        {
            delete m_vc;
            m_vc = NULL;
        }
        //释放内存条零件指针
        if (m_sto != NULL)
        {
            delete m_sto;
            m_sto = NULL;
        }
    }
private:
    CPU* m_cpu;//CPU零件指针
    VideoCard* m_vc;//显卡零件指针
    Storage* m_sto;//内存条零件指针
};
//Intel
class IntelCPU :public CPU
{
public:
    virtual     void calculate()
    {
        cout << "Intel的CPU开始计算了" << endl;
    }
};
class IntelVideoCard :public VideoCard
{
public:
    virtual     void display()
    {
        cout << "Intel的显卡开始显示了" << endl;
    }
};
class IntelMemory :public Storage
{
public:
    virtual     void storage()
    {
        cout << "Intel的内存条开始存储了" << endl;
    }
};
//Lenovo
class LenovoCPU :public CPU
{
public:
    virtual     void calculate()
    {
        cout << "Lenovo的CPU开始计算了" << endl;
    }
};
class LenovoVideoCard :public VideoCard
{
public:
    virtual     void display()
    {
        cout << "Lenovo的显卡开始显示了" << endl;
    }
};
class LenovoMemory :public Storage
{
public:
    virtual     void storage()
    {
        cout << "Lenovo的内存条开始存储了" << endl;
    }
};
//组装电脑
void test01()
{
    //创建第一台电脑
    Computer* c1 = new Computer(new IntelCPU,new IntelVideoCard, new IntelMemory);
    c1->work();
    delete c1;
    cout << "***********************" << endl;
    //组装第二台电脑
    Computer* c2 = new Computer(new LenovoCPU, new LenovoVideoCard, new LenovoMemory);
    c2->work();
    delete c2;
    cout << "***********************" << endl;
    //组装第三台电脑
    Computer* c3 = new Computer(new LenovoCPU, new IntelVideoCard, new LenovoMemory);
    c3->work();
    delete c3;
}
void main()
{
    test01();
    system("pause");
}