#include <iostream>
using namespace std;
 
class BaseInterface                                       
{ virtual void test()=0; };                              // abstract class
 
class ExtendedInterface : public virtual BaseInterface   // virtual inheritance
{};                                                      // abstract class
 
class Base : public virtual BaseInterface                // virtual inheritance
{ void test() override {} };                             // concrete class
 
class Extended : public ExtendedInterface, public Base   // multiple 
{};                             // thanks to virtual inheritance, concerete class 
 
int main() {
	Extended e; 
	return 0;
}

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