Gist for the FeatureLearn Erlang course (1.15)

pattern_matching.erl

% @doc Pattern Mathing module for the 1.15 step of the FutureLearn Erlang Course.
-module(pattern_matching).

-export([
  xOr/2,
  xOr1/2,
  xOr2/2,
  xOr3/2,
  xOr4/2,
  max_three/3,
  how_many_equal/3
]).

% Exclusive Or from lesson

xOr(X,X) -> false;
xOr(_,_) -> true.

% Exclusive Or implementations

xOr1(true,true) -> false;
xOr1(false,false) -> false;
xOr1(_,_) -> true.

xOr2(true, false) -> true;
xOr2(false, true) -> true;
xOr2(_,_) -> false.

xOr3(X,Y) -> X =/= Y.

xOr4(X,Y) -> not X == Y.

% @doc Given three integers returns the maximum
max_three(X,Y,Z) -> max(X, max(Y,Z)).

% @doc Given three integers returns a number representing the equivalent ones
how_many_equal(X,X,X) -> 3;
how_many_equal(X,X,_) -> 2;
how_many_equal(X,_,X) -> 2;
how_many_equal(_,X,X) -> 2;
how_many_equal(_,_,_) -> 0.

test_pattern_matching.erl

-module(test_pattern_matching).

-export([
    test_max_three/0,
    test_how_many_equal/0
]).

test_max_three() ->
  4 = pattern_matching:max_three(4, 2, 0),
  4 = pattern_matching:max_three(2, 4, 0),
  4 = pattern_matching:max_three(0, 2, 4),
  ':: max_three tests passed succesfully'.

test_how_many_equal() ->
  3 = pattern_matching:how_many_equal(4,4,4),
  2 = pattern_matching:how_many_equal(4,4,0),
  2 = pattern_matching:how_many_equal(4,0,4),
  2 = pattern_matching:how_many_equal(0,4,4),
  0 = pattern_matching:how_many_equal(4,2,0),
  ':: how_many_equal tests passed succesfully'.

Great solution. You should check my comment in FutureLearn about styles and tests.

Great solution. You should check my comment in FutureLearn about styles and tests.

Thanks. I liked your proposal and updated the code a little bit. I'll be posting in the course.

It looks nice! If you want to comply with common_test conventions (which might be useful for you in the future) your tests should return something like…

{comment, ""}.

But since you're not using CT yet… it doesn't matter.

It looks nice! If you want to comply with common_test conventions (which might be useful for you in the future) your tests should return something like…

{comment, ""}.

But since you're not using CT yet… it doesn't matter.

What does CT stand for?

What does CT stand for?

Common Test ;)

What does CT stand for?

Common Test ;)

Thanks @elbrujohalcon 👍 !