#include <iostream>
#include <vector>
#include <initializer_list>
 
class my_class
{
    std::vector<int> A;
public:
    my_class(std::initializer_list<int> v) : A(v) {}
 
 
    friend std::ostream& operator<<(std::ostream& out, const my_class& obj);
};
std::ostream& operator<<(std::ostream& out, const my_class& obj)
{
    for(const auto& it: obj.A) out << it << " ";
    return out;
}
 
int main()
{
    my_class obj = {1,2,3,4};
    std::cout << obj << std::endl;
    return 0;
}