#include <iostream>
#include <array>

#if 1 // Not in C++11 // make_index_sequence
#include <cstdint>

template <std::size_t...> struct index_sequence {};

template <std::size_t N, std::size_t... Is>
struct make_index_sequence : make_index_sequence<N - 1, N - 1, Is...> {};

template <std::size_t... Is>
struct make_index_sequence<0u, Is...> : index_sequence<Is...> {};

#endif // make_index_sequence

namespace detail
{
    template <typename T, std::size_t...Is>
    constexpr std::array<T, sizeof...(Is)> make_array(T val, index_sequence<Is...>)
    {
        return {(static_cast<void>(Is), val)...};
    }
}

template <std::size_t N, typename T>
constexpr std::array<T, N> make_array(T val)
{
    return detail::make_array(val, make_index_sequence<N>());
}

int main()
{
    constexpr auto a = make_array<5>(42);
    
    for (auto e : a) {
    	std::cout << e << std::endl;
    }
    return 0;
}