#include <array>
#include <iostream>
int main(){
    
  std::cout << std::endl;
  std::array<int, 4> arr= {1, 2, 3, 4};
  for ( auto a: arr){ std::cout << a << " " ; }
  std::cout << std::endl;
  arr[0]=1000;
  arr[2]=5;
  for ( auto a: arr){ std::cout << a << " " ; }
  std::cout << std::endl;
  arr.at(0)= '2';
  arr.at(2)= 'c';
  for ( auto a: arr){ std::cout << a << " " ; }
  std::cout << std::endl;
  arr.at(100)= 'l';
}