8.10 정적 멤버 변수

#include <iostream>

using namespace std;

int generateID()
{
	static int s_id = 0;
	return ++s_id;
}

int main()
{
	cout << generateID() << endl;
	cout << generateID() << endl;
	cout << generateID() << endl;
	
	return 0;
}

// 1
// 2
// 3

 

#include <iostream>

using namespace std;

class Something
{
	public:
	static int s_value;	// static 멤버 변수는 이니셜라이즈 불가!
};

int Something::s_value = 1;

int main()
{
	Something st1;
	Something st2;
	
	st1.s_value = 2;
	
	cout << &st1.s_value << " " << st1.s_value << endl;
	cout << &st2.s_value << " " << st2.s_value << endl;
	
	return 0;
}

// 0x55b77c704010 2
// 0x55b77c704010 2

 

#include <iostream>

using namespace std;

class Something
{
	public:
	static int s_value;	// static 멤버 변수는 이니셜라이즈 불가!
};

int Something::s_value = 1;	// define in cpp

int main()
{
	cout << &Something::s_value << " " << Something::s_value << endl;
	
	Something st1;
	Something st2;
	
	st1.s_value = 2;
	
	cout << &st1.s_value << " " << st1.s_value << endl;
	cout << &st2.s_value << " " << st2.s_value << endl;
	
	Something::s_value = 1024;
	
	cout << &Something::s_value << " " << Something::s_value << endl;
	
	return 0;
}

// 0x55e452a97010 1
// 0x55e452a97010 2
// 0x55e452a97010 2
// 0x55e452a97010 1024