//
// Program:  fibonacci
// 
// Purpose:  test recursive function to compute the Nth
//   Fibonacci number.  The Nth Fibonacci number F(N) is
//   defined to be:
//     N, if N is 0 or 1.
//     F(N-1) + F(N-2), if N > 1. 
//
// Input: 
//    N (which number to display).
// Output:
//   the Nth Fibonacci number.
//
#include <iostream.h>
#include <stdlib.h>		// has EXIT_SUCCESS

// Function to compute n-th Fibonacci number.
// Pre:  n >=0.
// Post:  returns n-th Fibonacci number.
int fibonacci(int n)
{
  if (n < 2)
    return n;
  else
    return fibonacci(n-1) + fibonacci(n-2);
}

// Main program.
int main(void)
{
  int n;
  cout << "Enter a non-negativer number:  ";
  cin >> n;
  if (n < 0)
    cout << "Number is negative\n";
  else
    cout << "For n = " << n << ", the n-th Fibonacci number is "
	 << fibonacci(n) << endl;
  return EXIT_SUCCESS;
}