Guess the number!

guess.exs

defmodule Guess do
  def make_guess(n, low..high), do: make_guess(n, low..high, div(low + high, 2))

  defp make_guess(n, _range, guess) when guess == n, do: IO.puts(n)

  defp make_guess(n, _low..high, guess) when guess < n do
    with low = guess + 1,
         guess = div(low + high, 2) do
      IO.puts("Is it #{guess}")
      make_guess(n, low..high, guess)
    end
  end

  defp make_guess(n, low.._high, guess) when guess > n do
    with high = guess - 1,
         guess = div(low + high, 2) do
      IO.puts("Is it #{guess}")
      make_guess(n, low..high, guess)
    end
  end
end