******** fig10.41 **********

	unsigned int
	fibonacci( unsigned int n )
	{
		unsigned int i, last, next_to_last, answer;

		if( n <=1 )
			return 1;

		last = next_to_last = 1;
		for( i=2; i<=n; i++ )
		{
			answer = last + next_to_last;
			next_to_last = last;
			last = answer;
		}
		
		return answer;
	}