-module(adder).
-compile(export_all).

adder() ->
    receive
	{add, X, Y, Sender} ->
	    Sender ! {sum, X+Y},
	    adder();
	stop ->
	    ok
    end.
	
start() ->
    Pid1=spawn(fun adder/0),
    register(adder, Pid1),
    ok.

add(Pid1, X, Y) ->
    Self=self(),
    Pid1 ! {add, X, Y, Self},
    receive
	{sum, Sum1} ->
	    Sum1
    end,
    Sum1.