Assignment 2.13

a213.erl

%%% assignment 2.13

-module(a213).
-include_lib("eunit/include/eunit.hrl").
-created_by("Marcelo Ruiz Camauër").

-export([nub/1]).

%% contains() copied from Jeremiah B.:
contains([], _Y) ->
   false;
contains([X|_Xs], Y) when X == Y ->
   true;
contains([_X|Xs], Y) ->
   contains(Xs, Y).


%% Define a function nub to remove all the duplicate elements from a list. 
nub(X)->nub(X,[]).

nub([],Unique)->Unique;               % nothing left to process, return list of Unique as the result.
nub([H|T],Unique)->                     % is current H in list of Unique? 
    case contains(Unique,H) of
        true ->  nub(T,Unique);     % H is not in Unique, so add it to Unique
        false -> nub(T,lists:append(Unique,[H]))          %  present in Unique, so skip it and continue
    end.


%%%%%%%%%%%%%%%
% invoke with 'a213:tests().' or "eunit:test(a213)."
nub_test()->
    [   ?_assert(nub([2,4,1,3,3,1])==[2,4,1,3]),
        ?_assert(nub([])==[])
    ].