Can the scope resolution operator be used in the definition of a member function when the member function is defined outside of its class definition?

Question

Can the scope resolution operator be used in the definition of a member function when the member function is defined outside of its class definition? Like this:

class Myclass{
    private:
    void foo();
    public:
    void foo2();
};

void Myclass::foo()
    {
    // do stuff. . . 
    }

My teacher gave us notes that demonstrate the use of the scope resolution operator only for member functions that are public. Can anyone clear this up?