#include <iostream>

using namespace std;

struct B{
public:
    void display(void) const {
        cout << "B's display." << endl;
    }

    virtual void vdisplay(void) const {
        cout << "B's vdisplay." << endl;
    }

    void hiddendisplay(void) const {
        cout << "F*ck who hid me" << endl;
    }
};

struct D : private B {
public:
    void display(void) const {
        cout << "non-virtual D's display" << endl;
    }

    void vdisplay(void) const {
        cout << "D!" << endl;
    }
};

int main(void){
    B *b = new B();
    b->display();
    b->vdisplay();
    b->hiddendisplay();
    delete(b);

    D *d = new D();
    d->display();
    d->vdisplay();
    d->hiddendisplay();
    delete(d);

    return 0;
}

In function 'int main()':
Line 15: error: 'void B::hiddendisplay() const' is inaccessible
compilation terminated due to -Wfatal-errors.