#include <iostream>
#include <string>

int main(int argc, char** argv)
{
  std::string s1 = "Hello World";
  std::cout << s1 << "." << std::endl;

  // begin and end iterators
  // H e l l o   W o r l d
  for (std::string::iterator i = s1.begin(); i != s1.end() ; ++i)
  {
    std::cout << *i << " ";
  }
  std::cout << "." << std::endl;
  
  // reverse begin and end iterators
  // d l r o W   o l l e H
  for (std::string::reverse_iterator ri = s1.rbegin(); ri != s1.rend() ; ++ri)
  {
    std::cout << *ri << " ";
  }
  std::cout << "." << std::endl;

  return 0;
}