class("Monday", ["System Programming", "Principles of Programming Languages"]).
class("Tuesday", ["Artificial Intelligence", "Human Computer Interaction"]).
class("Wednesday", ["Database Technologies"]).
class("Thursday", ["Artificial Intelligence", "Human Computer Interaction"]).
class("Friday", ["System Programming", "Principles of Programming Languages"]).

days(["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"]).

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

append([],X,X).
append([X|Y],Z,[X|W]) :-
    append(Y,Z,W).


daysOfClass(Days, [], Class):-
    Days = [],
    write("No Such Class Exist!");
    write(Days).

daysOfClass(Days, [H|T], Class):-
    class(H, Classes),
    member(Class, Classes),
    append(Days, [H], Result),
    daysOfClass(Result, T, Class);
    daysOfClass(Days, T, Class).

classesOnDay(Day, Classes):-
    class(Day, Classes),
    write(Classes);
    write("No Classes Found!").

?- days(D),
daysOfClass(Days, D, "System Programming"),
classesOnDay("Monday", Classes).