apbarrero

-module(first).
-export([double/1,mult/2,area/3,sq/1,treble/1]).

mult(X,Y) ->
    X*Y.

double(X) ->
    mult(2,X).

area(A,B,C) ->

apbarrero

-module(recurs).
-export([fib/1, pieces/1]).

fib(1) ->
   [0];
fib(2) ->
   [1,0];
fib(N) when N>2 ->
   L = fib(N-1),
   [X|Xs] = L,

apbarrero

-module(tailrecurs).
-export([fib/1, perfect/1, testPerfect/0]).

fib(0) -> 0;
fib(1) -> 1;
fib(N) when N>1 ->
   fib(N, 1, 0).

fib(2, Acc1, Acc2) -> Acc1 + Acc2;
fib(N, Acc1, Acc2) when N>2 -> fib(N-1, Acc1 + Acc2, Acc1).

apbarrero

-module(lists1).
-export([product/1, maximum/1]).

product(Xs) -> product(Xs, 1).
product([], P) -> P;
product([X|Xs], P) -> product(Xs, X*P).

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