总时间限制: 

1000ms

 

内存限制: 

65536kB

描述

代码填空，使得程序能够自动统计当前各种动物的数量

#include <iostream>
using namespace std;

// 在此处补充你的代码

void print() {
	cout << Animal::number << " animals in the zoo, " << Dog::number << " of them are dogs, " << Cat::number << " of them are cats" << endl;
}

int main() {
	print();
	Dog d1, d2;
	Cat c1;
	print();
	Dog* d3 = new Dog();
	Animal* c2 = new Cat;
	Cat* c3 = new Cat;
	print();
	delete c3;
	delete c2;
	delete d3;
	print();
}

输入

无

输出

0 animals in the zoo, 0 of them are dogs, 0 of them are cats
3 animals in the zoo, 2 of them are dogs, 1 of them are cats
6 animals in the zoo, 3 of them are dogs, 3 of them are cats
3 animals in the zoo, 2 of them are dogs, 1 of them are cats

样例输入

None

样例输出

0 animals in the zoo, 0 of them are dogs, 0 of them are cats
3 animals in the zoo, 2 of them are dogs, 1 of them are cats
6 animals in the zoo, 3 of them are dogs, 3 of them are cats
3 animals in the zoo, 2 of them are dogs, 1 of them are cats


答案：

#include <iostream>
using namespace std;
// 在此处补充你的代码
class Animal{
public:
    static int number;
    Animal(){
        number++;
    }
    virtual ~Animal()
    {
        number--;
    }
};
int Animal::number=0;
class Dog:public Animal{
public:
    static int number;
    Dog()
    {
        number++;
    }
    ~Dog()
    {
        number--;
    }
};
int Dog::number=0;
class Cat :public Animal{
public:
    static int number;
    Cat()
    {
        number++;
    }
    ~Cat()
    {
        number--;
    }
};
int Cat::number=0;
void print() {
    cout << Animal::number << " animals in the zoo, " << Dog::number << " of them are dogs, " << Cat::number << " of them are cats" << endl;
}
void print() {
    cout << Animal::number << " animals in the zoo, " << Dog::number << " of them are dogs, " << Cat::number << " of them are cats" << endl;
}

int main() {
    print();
    Dog d1, d2;
    Cat c1;
    print();
    Dog* d3 = new Dog();
    Animal* c2 = new Cat;
    Cat* c3 = new Cat;
    print();
    delete c3;
    delete c2;
    delete d3;
    print();
}