C++多态虚析构和纯虚析构的实现

#include<iostream>
#include<string>
using namespace std;
//虚析构和纯虚析构
class Animal
{
public:
	Animal()
	{
		cout << "调用了父类的构造函数" << endl;	
	}
	~ Animal()
	{
		cout << "调用了父类的析构函数" << endl;
	}
	virtual void speak() = 0;//纯虚函数
};
class Cat :public Animal
{
public:
	string *m_Name;
	//在子类的构造函数，加入小猫的姓名
	Cat(string name)
	{
		cout << "调用了子类-小猫类的构造函数" << endl;
		m_Name = new string(name);//在堆区创建
	}
	~Cat()
	{
		if (m_Name != NULL)
		{
			delete m_Name;
			m_Name = NULL;
			cout<<"调用了子类-小猫类的析构函数"<<endl;
		}
	}
	virtual void speak()
	{
		cout << *m_Name<<"小猫在说话" << endl;//解引用
	}
};
void testSpeak()
{
	Animal *animal = new Cat("Tom");//有参构造函数
	animal->speak();
	delete animal;
}
int main()
{
	testSpeak();
}

//虚析构和纯虚析构
class Animal
{
public:
	Animal()
	{
		cout << "调用了父类的构造函数" << endl;	
	}
	virtual ~ Animal()
	{
		cout << "调用了父类的析构函数" << endl;
	}
	virtual void speak() = 0;//纯虚函数
};

//虚析构和纯虚析构
class Animal
{
public:
	Animal()
	{
		cout << "调用了父类的构造函数" << endl;	
	}
	//virtual ~ Animal()
	//{
	//	cout << "调用了父类的析构函数" << endl;
	//}
	virtual ~Animal() = 0;//纯虚析构
	virtual void speak() = 0;//纯虚函数
};
Animal::~Animal()
{
	cout << "调用了父类的纯虚析构函数" << endl;
}