:- initialization(main).
main :- (father(ajay, bobby) -> write('yes father'), nl;
write('no father'), nl),
(mother(mary, lisa) -> write('yes mother', nl);
write('no mother'), nl),
halt.

%Facts
male(ajay).
male(bobby).
male(chatur).
male(david).
male(akash).
female(emma).
female(lisa).
female(mary).
female(jerry).
female(miya).
parent(ajay,bobby).
parent(bobby,lisa).
parent(mary,jerry).
parent(jerry,lisa).
parent(akash,miya).
parent(ajay,david).



%Rules
father(X,Y):- parent(X,Y),
        male(X).

mother(X,Y):- parent(X,Y),
         female(X).

brother(X,Y):- parent(Z,X),
          parent(Z,Y),
          male(X),
          Y\==Z.

sister(X,Y):- parent(Z,X),
          parent(Z,Y),
          female(X),
          Y\==Z.

grandfather(X,Y):- father(X,Z),
              parent(Z,Y).

Prolog online compiler

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About Prolog

Prolog (Programming in Logic) is a logic programming language associated with artificial intelligence and computational linguistics. It works through facts, rules, and queries, using a form of symbolic reasoning known as backward chaining. Prolog is declarative, meaning you describe what you want instead of how to compute it.

Sample Code

The following is a simple Prolog program that prints a greeting:

:- initialization(main).

main :-
    write('Hello, World!').

Syntax Basics

Facts

Facts represent basic assertions about the world.

likes(alice, pizza).
likes(bob, pasta).

Rules

Rules define logical relationships using facts.

friends(X, Y) :- likes(X, Z), likes(Y, Z).

Queries

Queries are used to find information based on facts and rules.

?- likes(alice, What).

Operators

OperatorDescription
:-Rule definition
,Logical AND
;Logical OR
=Unification

Lists

member(X, [X|_]).
member(X, [_|T]) :- member(X, T).

Recursion

Prolog heavily relies on recursion.

factorial(0, 1).
factorial(N, F) :-
  N > 0,
  N1 is N - 1,
  factorial(N1, F1),
  F is N * F1.

This guide provides a quick reference to Prolog programming syntax and features. Start writing Prolog code using OneCompiler’s Prolog online compiler today!