third.erl

-module(third).
-export([xOr_1/2, xOr_2/2, xOr_3/2, maxThree/3, howManyEqual/3]).

% XOR implementation #1
xOr_1(A,A) ->
  false;
xOr_1(A,B) ->
  A or B.

% XOR implementation #2
xOr_2(true,B) ->
  not B;
xOr_2(_,B) ->
  B.

% XOR implementation #3
xOr_3(A,B) ->
  A =/= B.

% Max of three using pattern matching
maxThree(A,A,A) -> A;
maxThree(A,B,A) -> max(A,B);
maxThree(A,A,B) -> max(A,B);
maxThree(A,B,B) -> max(A,B);
% We could just use this, but we are supposed to pattern match here!
maxThree(A,B,C) ->
  M=max(A,B),
  max(M,C).

% How many equal using pattern matching
howManyEqual(A,A,A) -> 3;
howManyEqual(A,A,_) -> 2;
howManyEqual(_,A,A) -> 2;
howManyEqual(A,_,A) -> 2;
howManyEqual(_,_,_) -> 0.