#include <type_traits>

int main()
{
    static_assert( std::is_same_v< largest_type<int>::type, int > );
    
    static_assert( std::is_same_v< largest_type_t<int>, int > );
    static_assert( std::is_same_v< largest_type_t<int, char>, int > );
    static_assert( std::is_same_v< largest_type_t<int, char, double>, double > );
}