How to avoid repetition in prolog

Question

I get several results with the same outputs.

I want to get jack,jane only one time, but I get it two times.

How can I avoid this? I tried setof but I couldn't get it done. Please can someone help me on this?

Answer 1

try this link

Answer 2

This question is duplicated in "How to stop repetitions in rules in prolog".

An answer is to do something like this:

solve :-
    marriedcouple(Dad, Mum),
    not(found(marriedcouple(Dad, Mum))),
    assert(found(marriedcouple(Dad, Mum))),
    write([Dad, Mum]),
    nl,
    fail.

Read the full answer for more detail.