text: #include <iostream>
  #include <iterator>
  #include <cstddef>
  
  using std::cout;
  using std::endl;
  
  using std::begin;
  using std::end;
  
  using std::ptrdiff_t;
  
  int main() {
      constexpr ptrdiff_t a_size = 40;
      int a[a_size];
      for (auto beg = begin(a); beg != end(a); ++beg)
          *beg = 0;
  
      for (auto n : a)
          cout << n << ' ';
      cout << endl;
  
      return 0;
  }
  