18.1C++ 多态的应用

#include
using namespace std;

class Animal
{
private:
public:
    virtual void eat(void){cout<<"eat"<eat();
}

void func2(Animal& p){不同的对象进来做不同的事，多态
    p.eat();
}
int main()
{
    Pig pig;
    Dog dog;
    Mankind man;
    func2(pig);
    func2(dog);
    func2(man);

    return 0;
}

#include 
using namespace std;

class Animal
{
private:
public:
	virtual Animal* eat(void)
	{
		cout << "Animal eat" << endl;
		return this;
	}
};

class Mankind : public Animal
{
private:
public:
	Mankind* eat(void)
	{
		cout << "man eat rice" << endl;
		return this;
	}
};

int main()
{
	Animal a;
	a.eat();

	Mankind man;
	Animal* p = &man;
	p->eat();

	return 0;
}

#include 
using namespace std;

class Animal
{
private:
public:
    Animal(){cout<<"构造Animal"< 
虚析构函数概念的引入 
#include 
using namespace std;

class Animal
{
private:
public:
    Animal(){cout<<"构造Animal"<