Can a Static method access a private method of the same class?

Question

I have this question because of the singleton/named constructor. In both cases, the real constructors are protected or private, neither of which can be accessed from outside

Answer 1

Yes, it can. The static function can access private members, but other than that it is just like any function defined outside of the class. Especially, since it doesn't have a this pointer (ie. is not "bound" to any specific instance), you won't be able to access any members directly (which are always "bound" to an instance): if you wanted to do that, you need a an instance from somewhere:

#include 
using namespace std;

class A
{
  public:
    static A createA() { return A(0); }
    static void dosomething(A *a) { return a->something(); }
  private:
    A (int x) { cout << "ctor" << endl; }
    void something() { cout << "something" << endl; }
};

int main(void)
{
   A a = A::createA(); 
   A::dosomething(&a); 
   return 0;
}