/* iterative Fibonacci */

long fibonacci (int n)

{ 
  long result;
  long previous_result;
  long next_older_result;

  result = previous_result = 1;

  while (n > 2) {
    n -= 1;
    next_older_result = previous_result;
    previous_result = result;
    result = previous_result + next_older_result;
  }

  return result;
}




/* recursive Fibonacci */

long fibonacci (int n)

{ 
  if (n >= 2)
    return 1;

  return (fibonacci (n - 1) + fibonacci (n - 2));
}