RosettaCodeData/Task/Averages-Simple-moving-average/Erlang/averages-simple-moving-average-1.erl
2023-07-01 13:44:08 -04:00

41 lines
918 B
Erlang

main() ->
SMA3 = sma(3),
SMA5 = sma(5),
Ns = [1, 2, 3, 4, 5, 5, 4, 3, 2, 1],
lists:foreach(
fun (N) ->
io:format("Added ~b, sma(3) -> ~f, sma(5) -> ~f~n",[N,next(SMA3,N),next(SMA5,N)])
end, Ns),
stop(SMA3),
stop(SMA5).
sma(W) ->
{sma,spawn(?MODULE,loop,[W,[]])}.
loop(Window, Numbers) ->
receive
{_Pid, stop} ->
ok;
{Pid, N} when is_number(N) ->
case length(Numbers) < Window of
true ->
Next = Numbers++[N];
false ->
Next = tl(Numbers)++[N]
end,
Pid ! {average, lists:sum(Next)/length(Next)},
loop(Window,Next);
_ ->
ok
end.
stop({sma,Pid}) ->
Pid ! {self(),stop},
ok.
next({sma,Pid},N) ->
Pid ! {self(), N},
receive
{average, Ave} ->
Ave
end.