C++ generate tuple of arbitrary size initialised with default constructor

gen_tuple_n_size.cxx

#include <algorithm>
#include <tuple>
#include <iostream>

// That was an amazing display
//https://stackoverflow.com/a/37094024/338107

template<size_t, class T>
using T_ = T;

template<class T, size_t... Is>
auto gen(std::index_sequence<Is...>) { return std::tuple<T_<Is, T>...>{}; }

template<class T, size_t N>
auto gen() { return gen<T>(std::make_index_sequence<N>{}); } 

int main()
{
    constexpr unsigned N = 3;
    auto tup = gen<int, N>();
    auto [x, y, z] = tup;
    std::cout << x << ", " << y << ", " << z << std::endl;
}