Prolog help

[5143LS]

Hi!

Want help with some Prolog assignments:

1. Find the maximum and minimum in a list of numbers.

2. Find out if a given predicate is a member of a list, ex. member(X,L) checks if X is part of list L.

How do I start? Any ideas?

Thank you

/Clark

 

[mizt]

thats pretty easy..

Something is the member of a list if it is the Head of the list or if it is in the tail of the list..

so

member(X, [X,Head]).

member(X, [Head,Tail]):- member(X, Tail).

Hope that helps..

Euan

 

[5143LS]

Thank you!

 

[Guest_imported]

i search an games: the naval battle realizaed in prolog

 

[pimi]

member(X, [X,Head]).
member(X, [Head,Tail]):- member(X, Tail).

?- member(a, [c, b, a]).
no

Please replace some "," with "|".

member(X, [X|Head]).
member(X, [Head|Tail]) :- member(X, Tail).

?- member(a, [c, b, a]).
yes

 

[pimi]

To find the maximum in a list of numbers...

max([N1|Ns], Max) :-
maxsub(Ns, N1, Max).

maxsub([], MaxTmp, MaxTmp) :-
!.
maxsub([N1|Ns], MaxTmp, Max) :-
N1 > MaxTmp, !, maxsub(Ns, N1, Max).
maxsub([N1|Ns], MaxTmp, Max) :-
maxsub(Ns, MaxTmp, Max).

This pattern can be used also for minimum number.