menu(X) :- 
   write('\tClass roster management system'), nl,
   write('\t=============================='), nl,
   write('\t   MENU'), nl,
   write('\t=============================='), nl,
   write('\t0. Option 0'), nl,
   write('\t1. Option 1'), nl,
   write('\t2. Exit'), nl, 
   write('\tEnter your choice (followed by a \'.\'): '),
   read(Sel),
   process(Sel, X).

process(0, X) :-
    nl,
    write('\tGot option 0 here, print roster(X)'),nl,
    write(X),
    nl, nl, menu(X).

process(1, X) :- 
    nl,
    write('\tGot option 1 here.'),
    read_student_info([A, B]),
    nl, nl, menu([[A,B] | X]). /* just add it to roster */

process(2, _) :- write('Good-bye'), nl, !.
process(_, X) :- menu(X).

read_student_info([A, B]) :-
  write('\tStudent ID: '),
  read(A),
  write('\tStudent Name: '),
  read(B).