/* $Id: factorial.pl,v 321.2 2002-03-06 17:50:09-08 - - $ */

/*
* Factorial, the old intro to recursion standby.
*/

factorial( 0, 1 ) :-
	!.

factorial( N, Nfac ) :-
	M is N - 1,
	factorial( M, Mfac ),
	Nfac is N * Mfac.