chop.exs

defmodule Chop do
  def guess(actual, range = low..high) do
    _guess(actual, div(low+high, 2), range)
  end

  defp _guess(actual, actual, _) do
    "YOU GOT IT #{actual} it is!"
  end

  defp _guess(actual, attempt, low.._) when actual < attempt do
    guess(actual, low..attempt-1)
  end

  defp _guess(actual, attempt, _..high) when actual > attempt do
    guess(actual, attempt+1..high)
  end
end