#include "stdafx.h"

 #include <iostream>

 using namespace std;

 class A {

 public:

     virtual void f(){

         cout << "hello world" << endl;

     }

 };

 class B : virtual public A {

 public:

     virtual void f() override{

         cout << "hello" << endl;

     }

 };

 class C : virtual public A {

 };

 class Main : public B, public C{

 };

 int main(){

     Main* obj = new Main;

     obj->f();

     A* a = new Main;

     a->f();

     B* b = new Main;

     b->f();

     C* c = new Main;

     c->f();

 }

 interface A{

     default void f(){

         System.out.println("hello world");

     }

 }

 interface B extends A {

     @Override

     default void f(){

         System.out.println("hello");

     }

 }

 interface C extends A{

 }

 public class Main implements B, C{

     public static void main(String[] args) {

         Main obj = new Main();

         obj.f();

         A a = new Main();

         a.f();

         B b = new Main();

         b.f();

         C c = new Main();

         c.f();

     }

 }