MoreAboutStatic.cpp

#include <iostream>

class AA
{
public:
	static int i;
	//static int i = 0; // compile error
	static const int KKKK= 10;//OKAY
	int k = 0; //warning, just allow after c++/11 to initialize value in class
	void fool(){printf("the value of i is %d\n", i);}//static function only can use "static const", can't use "static" variables
};

class BB:public AA
{
public:
    static int i;
};
int AA::i = 5;
//the only way to initialize a "static" member variable.
//For "static const" member variable both to initialize here or in class is okay

int main(int argc, const char * argv[])
{
    AA::i=4;
	printf("Size of AA is %d\n", sizeof(AA));// only 4, won't count static member;
	AA* p = NULL;//new AA;
    AA* p2 = new AA;//new AA;
    p2->i=3;
	AA* q = NULL;//new AA;

	p->fool();
    
    //以下三種資料均為同一個.. 要注意
    printf("value of of AA::i=%d, address of AA::i=%d\n", AA::i, &AA::i);
	printf("value of of p->i=%d, address of p->i=%d\n", p->i, &p->i);
	printf("value of of q->i=%d, address of q->i=%d\n", q->i, &q->i);
	printf("value of of p2->i=%d, address of p2->i=%d\n", p2->i, &p2->i);
	return 0;
}