Elixir Exercises
Author: Tyler M. Masthay
CPS 49903: Emerging Languages, Spring 2017

Modify the program Counter2.ex
so that a private member variable currCount
is printed and modified.
 Implement a module for a binary tree closure that is purely functional.
Use the following representation: a leaf node is a tuple of the form
{:leaf, val} where val is the value associated with this
tree and an internal node is of the form {:internal, left, right}
where left and right are the associated subtrees. Ensure
that polymorphics trees are supported. For example, the tree {:internal,
{:leaf, 1}, {:leaf, fn(x) > x}} should be supported within the module.
 Use the binary tree from problem 2 to implement the foldl and
foldr functions from the Haskell programming language.