Second exercise in "Future Learn/Programming Erlang".

ex2.erl

-module(ex2).
-export([max_three/3, how_many_equal/3, how_many_equal_test/0, xor1/2, xor2/2, xor3/2]).



xor1(true, B) ->
       not B;
xor1(_, B) ->
	B.

xor2(A, false)->
	A;
xor2(false, B)->
	B;
xor2(_, _) ->
	false.

xor3(A, B) ->
	A =/= B.


max_three(A,B,C) ->
	max(A, max(B, C)).

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.

how_many_equal_test() ->
	[
	 how_many_equal(1,1,1) == 3,
	 how_many_equal("a", "b", "a") == 2,
	 how_many_equal("a", 3, 4) == 0,
	 how_many_equal("a", "a", 2) == 2
	].

Nice solution!
Stylistic/idiomatic Tip: It's more common in the Erlang community to use snake_case instead of camelCase for functions, modules, and atoms in general. Test frameworks like eunit, for instance, expect your test functions to be called something_something_test/0.

Thanks @elbrujohalcon. Updated the function names following your remarks. Too many Java habits :-(

😅