Multiply

Description

Multiplication as repeated addition.

Source: The Art of Prolog

Download

Program source code: multiply.pl

Listing

/*
	times(X,Y,Z) :-
		X, Y and Z are natural numbers
		such that Z is the product of X and Y
*/
 
	times(0,X,0).
	times(s(X),Y,Z) :- times(X,Y,XY), plus(XY,Y,Z).
 
	plus(0,X,X) :- natural_number(X).
	plus(s(X),Y,s(Z)):- plus(X,Y,Z).
 
	natural_number(0).
	natural_number(s(X)) :- natural_number(X).
 
%	Program 3.4: Multiplication as repeated addition
% ?- times(s(0),s(0),X).

Comments

pl/prolog/pllib/multiply.txt · ostatnio zmienione: 2017/07/17 08:08 (edycja zewnętrzna)
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