출처: http://xlos.tistory.com/869
//static data member들은모든block의밖에서define 되어야한다
//모든block의밖에서define되는static data memeber들은따로초기화값을주지않으면
//자동으로0으로초기화된다.
class Widget
{
static int n; //declaration
};
int Widget::n = 0; //definition
//const data member들은constructor's initialization section에서초기화가되어야한다.
//member initialization list
class Widget
{
public:
Widget() : n( 0 ) { }
private:
const int n; //const data member
};
//const static data member들은integral type일경우, in-class initialization이허용되고,
//non-integral type일경우, class 밖에서초기화되어야한다.
#include <string>
class Widget
{
public:
//..
private:
static const int MAX = 512; //definition
static const char flag = 'a'; //also a defintion
static const std::string msg; //non-integral type; must be defined outside the class body
};
const std::string Widget::msg = "hello";
* 참고
Integral type : bool, char, wchar_t, signed char, short int, int, long int, unsigned char, unsigned short int, unsigned int, unsigned long int
Floating-point type : float, double, long double
