Help pls

[mzam]

I am trying to write a clause for the following list handling rule : bubble(N,List,NewList) which binds NewList with the List having its Nth element brought to the front. e.g.bubble(3,[a,b,c,d,e],Ans). binds Ans to [c,a,b,d,e]
Here is my code. I don't know why it is not working. Can somebody helpppp me plsssss?? 10x

 del(1,[H1|T],T).

del(N,[H|T],[H|Rest]):- NewN is N - 1, 
                        
                        del(NewN,T,Rest).

bubble(N,[H|T],[H1|New]):-del(N,[H|T],New).

bubble(N,[_|T],[H|Rest]):- bubble(N,T,Rest).

 

[joel76]

You have almost the solution !
Just look at the clause (wich has a very bad name : del, it should be get !): del(1,[H1|T],T).
You loose the information that it's the element you must remember.
You should have del(1,[H,| T], H, T).
And the work is done !