class A {
public:
    int x;
protected:
    int y;
private:
    int z;
};

class B : public A {
    // x is public
    // y is protected
    // z is not accessible from B
};

class C : protected A {
    // x is protected
    // y is protected
    // z is not accessible from C
};

class D : private A {
    // x is private
    // y is private
    // z is not accessible from D
};