//	Fibo1.cc
//		Sec. 5.1 in Lecture
//		Demo of Fibonacci numbers
#include <iostream.h>
#include <math.h>
main()
{
  const int N = 20;
        int i;
        int x[N+1];		// !!   N + 1   !!
     double fib;
     
//		Calculate Fibonacci numbers
  x[0] = 0;
  x[1] = 1;
  for ( i = 2; i <= N; i++ )
   {
     x[i] = x[i-1] + x[i-2];
   }
  
//		Output x
  cout << endl;
  for ( i = 0; i <= N; i++ )
   {
     cout << i << " : " << x[i] << endl;
   }
  cout << endl;
  
///		Check last Fibonacci number  
  fib = ( pow(0.5*(1.0+sqrt(5.0)),N)
  	 -pow(0.5*(1.0-sqrt(5.0)),N)
	)/sqrt(5.0);
  
  cout << endl;
  cout << "fib(" << N << ") = " << fib << endl;
  cout << endl;
}