#include <iostream>

using namespace std;

struct A
{
    int i;
    
    A(int i): i(i) {}
};

struct B : A
{
    int j;
    
    B(int i): A(i), j() {}
};

int main()
{
    A a[] = {A(1), A(2), A(3)};
    B b[] = {B(4), B(5), B(6)};
    
    A * p = b;
    
    cout << p[1].i << endl;
}