% Fact statements
studies(charlie, cpsc376).
studies(olivia, cpsc376).
studies(jack, cpsc311).
studies(arthur, cpsc246).
teaches(lee, cpsc376).
teaches(kirke, cpsc311).
teaches(kirke, cpsc374).
teaches(juniper, cpsc246).
% Rule
professor(X, Y) :- teaches(X, C), studies(Y, C).
% Queries
% Query: charlie studies what?
% Query: What does charlie study?
% Example usage: ?- studies(charlie, What).
% This will return What = cpsc376.
% Enter the query in the Prolog console.
% Query: Who are the students of professor lee?
% Example usage: ?- professor(lee, Student).
% This will return all students Y such that teaches(lee, C) and studies(Y, C).
% Enter the query in the Prolog console.
:- initialization(main).
main :- write('Prolog program loaded. Type your queries.').
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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.
The following is a simple Prolog program that prints a greeting:
:- initialization(main).
main :-
write('Hello, World!').
Facts represent basic assertions about the world.
likes(alice, pizza).
likes(bob, pasta).
Rules define logical relationships using facts.
friends(X, Y) :- likes(X, Z), likes(Y, Z).
Queries are used to find information based on facts and rules.
?- likes(alice, What).
| Operator | Description |
|---|---|
:- | Rule definition |
, | Logical AND |
; | Logical OR |
= | Unification |
member(X, [X|_]).
member(X, [_|T]) :- member(X, T).
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!