private_inheritance.cpp

class B {
public:
    virtual void foo() {}
};

class C : private B {
public:
    void bar() { foo(); }
};

class D : public C {
public:
    //void baz() { foo(); } // error: ‘B’ is not an accessible base of ‘D’
    void baz() { bar(); }
};

int main()
{
    C c;
    //c.foo(); // error: ‘B’ is not an accessible base of ‘C’
    c.bar();   // this is fine, of course
    
    //B* bp (new C); // error: ‘B’ is an inaccessible base of ‘C’
}