当它是类数据成员时，如何调用指向成员函数的指针？

struct B
{
  void (B::*pf)(int, int);  // data member
  B () : pf(&B::foo) {}
  void foo (int i, int j) { cout<<\"foo(int, int)\\n\"; } // target method
};

int main ()
{
  B obj;
  // how to call foo() using obj.pf ?
}

obj.*pf(0,0);

error: must use ‘.*’ or ‘->*’ to call pointer-to-member function in ‘pf (...)’, e.g. ‘(... ->* pf) (...)’

(obj.*obj.pf)(0, 1);

.

(obj.*(obj.pf))(0, 1);

obj.*obj.pf(0, 1) /* or */ obj.*(obj.pf)(0, 1)

obj.*(obj.pf(0, 1)) // grammar expects obj.pf to be a callable returning a
                    // pointer to member

(obj.*obj.pf)(1, 2);

(obj.*obj.pf)(1, 2);