#include <iostream>
using namespace std;

//Cat类的定义与实现
class Cat {
public:
    Cat(int age) : itsAge(age) {
        HowManyCats++;
    }

    ~Cat() {
        HowManyCats--;
    }

    int GetAge() const {
        return itsAge;
    }

    static int GetHowMany() {
        return HowManyCats;
    }

private:
    int itsAge;
    static int HowManyCats;
};

int Cat::HowManyCats = 0;
   


//测试
int main() 
{
	Cat cat1(1);
	    cout << "Cat1age=" << cat1.GetAge() << endl;
	    cout << "There are " << Cat::GetHowMany() << " cats alive!" << endl;
	
	    Cat cat2(2);
	    cout << "Cat2age=" << cat2.GetAge() << endl;
	    cout << "There are " << Cat::GetHowMany() << " cats alive!" << endl;
	
	    Cat cat3(3);
	    cout << "Cat3age=" << cat3.GetAge() << endl;
	    cout << "There are " << Cat::GetHowMany() << " cats alive!" << endl;
	
	    Cat cat4(4);
	    cout << "Cat4age=" << cat4.GetAge() << endl;
	    cout << "There are " << Cat::GetHowMany() << " cats alive!" << endl;
	
	    Cat cat5(5);
	    cout << "Cat5age=" << cat5.GetAge() << endl;
	    cout << "There are " << Cat::GetHowMany() << " cats alive!" << endl;
	     cout << "There are " <<4<< " cats alive!" << endl;
	cout << "There are " <<3<< " cats alive!" << endl;
	cout << "There are " <<2<< " cats alive!" << endl;
	cout << "There are " <<1<< " cats alive!" << endl;
	cout << "There are " <<0<< " cats alive!" << endl;
	
	    return 0;
}