%--------
% change.pl
%
% adapted from: J. R. Fisher tutorial, section 2.8 
% last modified: 03-29-11                    
%
% making change for $1 
%--------

 change([NumHalfs,NumQtrs,NumDimes,NumNickls,NumCents]) :- 
     member(NumHalfs, [0, 1, 2]), 
     member(NumQtrs, [0, 1, 2, 3, 4]),
     member(NumDimes, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]),
     member(NumNickls, 
/*[20, 19, 18, 17, 16, 15, 14, 13, 12,
                        11, 10, 9,8,7,6,5,4,3,2,1,0]),*/
                      [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,        
                       11, 12, 13, 14, 15, 16, 17, 18, 19, 20]), 
     Subtotal is ((50 * NumHalfs) + (25 * NumQtrs) + 
               (10 * NumDimes) + (5* NumNickls)), 
     Subtotal =< 100, 
     NumCents is 100-Subtotal.