March 2014 update

Task/Forward-difference/Erlang/forward-difference.erl

@@ -0,0 +1,18 @@
+-module(forward_difference).
+-export([difference/1, difference/2]).
+
+-export([task/0]).
+-define(TEST_DATA,[90, 47, 58, 29, 22, 32, 55, 5, 55, 73]).
+
+difference([X|Xs]) ->
+    {Result,_} = lists:mapfoldl(fun (N_2,N_1) -> {N_2 - N_1, N_2} end, X, Xs),
+    Result.
+
+difference([],_) -> [];
+difference(List,0) -> List;
+difference(List,Order) -> difference(difference(List),Order-1).
+
+task() ->
+    io:format("Initial: ~p~n",[?TEST_DATA]),
+    [io:format("~3b: ~p~n",[N,difference(?TEST_DATA,N)]) || N <- lists:seq(0,length(?TEST_DATA))],
+    ok.