int IterativeRabbit(int N)
// Iterative solution to the rabbit problem.
{
   // initialize base cases:
   int Previous = 1;       // initially Rabbit(1)
   int Current = 1;        // initially Rabbit(2)
   int Next = 1;           // result when N is 1 or 2

   // compute next Rabbit values when N >= 3
   for (int I = 3; I <= N; ++I)
   {  // Current is Rabbit(I-1), Previous is Rabbit(I-2)
      Next = Current + Previous;  // Rabbit(I)

      Previous = Current;         // get ready for
      Current = Next;             // next iteration
   }  // end for

   return Next;
}  // end IterativeRabbit