#include <iostream>
using namespace std;
class Itest{
public:
	void fun(){cout<<"hello";};
	int aaa;
};
class test:public Itest{
public:
	void fun(){cout<<"hello world.";}
	int a1;
};
int main(){
	test* a=new test();
	a->a1=10;
	a->aaa=10;
	Itest* b=a;

	test* c=(test*) b;
	cout<<c->a1;
	return 0;
}