5-6

 #include <iostream>using namespace std;class A{public:void f1();protected:void f2();private:int i;};class B:public A{public:void f3();int k;private:int m;};class C:protected B {public:void f4();protected:int n;private:int p;};class D:private C{public:void f5();protected:int q;private:int r;};int main(){ A a1; B b1; C c1; D d1; return 0;}