-module(q2).
-export( [init/0, push/2, pop/1]).

init() -> {queue, [],[]}.

push( {queue, A,B},X) -> {queue, A, [X|B]}.

pop( {queue, [X|A], B} ) -> { X, {queue, A,B} };
pop( {queue, [], B} ) -> 
     [First|Rest] = lists:reverse(B),
     { First, {queue, Rest, []} }.