C++输出运算重载为成员函数

#include
using namespace std;
class A{
	public:
		ostream & operator << (ostream& out){
			out << a << b;
			return out;
		}
	private:
		int a = {10};
		int b = {100};
};
int main(){
	A a;
	a << cout << endl;
	return 0;
}

成员函数的话，只能这样使用了！