C++ private "hack"

class b;

class a
{
private:
    a()
    {
    };

    friend b;

    int aa = 2;
};

class b
{
public:
    b()
    {
        c.aa = 2;
    };

    int Get()
    {
        return c.aa;
    };

    a c;
};

int main()
{
    b ss;
    printf("%d\n", ss.Get());