初始化static成员

 

//Cat.h

class Cat

{

public:

Cat(int age):its_age(age) {

HowManyCats++;

}

virtual ~Cat() {

HowManyCats--;

}

virtual int get_age();

virtual void set_age(int);

static int get_how_many() {return HowManyCats;}

private:

int its_age;

static int HowManyCats;

};

 

//Cat.cpp

 

#include "Cat.h"

int Cat::get_age()

{

return its_age;

}

void Cat::set_age(int age)

{

its_age=age;

}

 

int Cat::HowManyCats = 0; //初始化 static 成员