c++17 fold expression print function that can support 2,0000 element efficient

Question

Hello how can make it print it more efficient with large element like 20,000 element ? i took very long to compile , i try to follow this static const array of values in Variadic Template C++

but i can't make it work with fold expression, any ideas how to solve this problem

#include <iostream>


template<typename T = int , typename Comp=std::less<T>>
struct Facility
{
  template<T ... list> 
  struct List
  {
    static void print()
    {
      // store in static array to compile faster
      constexpr static T args[sizeof...(list)] = {list...}; 
      // use for idiom for each except the last, but this time in reserve way
      // assgn char* space to empty char first
      const char* space = "";
      if (sizeof...(list) == 0)
      {
        // simple just call space to cout , if not warning no variable used
        std::cout <<'"' <<"Empty List" <<'"' << space  <<std::endl;
      }
      else if  (std::is_same<T, char>::value)
      {
        std::cout << '"';
       ((std::cout << space << args), ...);// compile error
        // simple just call space to cout , if not warning no variable used
        std::cout << '"' << space<< std::endl;
      }
      else
      {
        std::cout << '"';
        // fold expression bracket,L side will execute first 
        // the first round space is empty and later on become space
        (((std::cout << space << list), space = " "), ...);
        std::cout << '"' << std::endl;
      }    
    }  
  }; 




template<int ... intlist>
using IntList = typename Facility<int>::List<intlist...>;

template<char ... charlist>
using CharList = typename Facility<char>::List<charlist...>;

template<short ... shortlist>
using ShortList = typename Facility<short>::List<shortlist...>;

template<unsigned short ... shortlist>
using UnsignedShortList = typename Facility<unsigned short>::List<shortlist...>;

template<long ... list>
using LongList = typename Facility<long>::List<list...>;

int main()
{
    std::cout << "********Testing Basic List Capabilities*********\n";  
    using List1 = IntList<1,2,3,4>;
    using List2 = IntList<9, 0, -1, -200>;
    using List3 = IntList<LONG20000LIST>;
    List1::print();
    List2::print();
    List3::print();

    using String1 = CharList<'a', 'b', 'c'>;
    using String2 = CharList<' ', 'w', 'o', 'r', 'l', 'd' >;
    using EmptyString = CharList<>;
    String1::print();
    String2::print();
    EmptyString::print();
    std::cout << "************Finished Testing *******************\n\n";
}

Answer 1

This is how you need to declare your array:

constexpr static T args[] = {list...};