#include <iostream>
#include <array>
using namespace std;

int main () {
  std::array<int,6> myarray = {10, 20, 30, 40, 50, 60} ;

  std::cout << "myarray fw:";
  for (auto it=myarray.cbegin() ; it < myarray.cend(); ++it )
    std::cout << ' ' << *it;   // cannot modify *it
  std::cout << '\n';
  
  cout << "myarray bw:";
  for (auto rit=myarray.crbegin() ; rit < myarray.crend(); ++rit )
    std::cout << ' ' << *rit;   // cannot modify *rit
  std::cout << '\n';
  
  std::cout << "myarray +10 fw:";
  for (auto it=myarray.cbegin() ; it < myarray.cend(); ++it ) {
    *it += 10;
    std::cout << ' ' << *it;   // cannot modify *it
  }
  std::cout << '\n';
  
  cout << "myarray +100 bw:";
  for (auto rit=myarray.rbegin() ; rit < myarray.rend(); ++rit ){
    *it += 100;
    std::cout << ' ' << *rit;   // cannot modify *rit
  }
  std::cout << '\n';
}