Need Help UnderStanding the Code

who([H|T], B) :-
	member(H, B), !,
	who(T, B).
	who([_|_], _).

I want to understand this code I am new to learn Prolog

Do you know about gtrace/0 ?

See: The Graphical Debugger

No actually Iam not familiar with gtrace/0


I tried the using trace but actually not getting what these predicates are actually doing for what task they were wriiten

Then you need to get a book and work through it.

One of the best places to ask such a question is stackoverflow as mentionned by EricGT. Apart from gtrace/0 a complementary way to make tests is to use different inputs and look at the results that you get.