# # This software is Copyright 2005 by Elsevier Inc. You may use it # under the terms of the license at http://perl.plover.com/hop/LICENSE.txt . # ### ### factorial2 ### ## Chapter 5 section 4.2 sub factorial { my ($n) = @_; my $product = 1; until ($n == 0) { $product *= $n; $n--; } return $product; }