// 多态本质:
// 父类引用或指针指向子类对象，通过父类指针或引用来（操作子类对象）调用子类中重写的成员函数
#include <iostream>
#include <cstring>
#include <cstdlib>

using namespace std;

class Animal
{
public:
    virtual void speak()
    {
        cout << "动物在唱歌..." << endl;
    }
};

class Dog : public Animal
{
public:
    void speak()
    {
        cout << "狗在唱歌..." << endl;
    }
};

void DoBusiness(Animal &animal)
{
    animal.speak();
}

int main()
{
    Dog dog;
    DoBusiness(dog);
    return 0;
}