Functional Programming in Erlange 2.6

w2a1.erl

-module(w2a1).
-export([maximum/1, 
        product/1,
        tail_maximum/1,
        tail_product/1]).

product([]) -> 1;
product([Num|Nums]) -> Num * product(Nums).

tail_product(Nums) -> tail_product(Nums, 1).

tail_product([], Acc) -> Acc;
tail_product([Num|Nums], Acc) ->
	tail_product(Nums, Num * Acc).

maximum([X|[]]) -> X;
maximum([X|Xs]) ->
	max(X, maximum(Xs)).

tail_maximum([X|[]]) -> X;
tail_maximum([X|Xs]) -> tail_maximum(Xs, X).

tail_maximum([X|[]], Acc) -> max(X, Acc);
tail_maximum([X|Xs], Acc) ->
	tail_maximum(Xs, max(X, Acc)).