Elixir Guesser

guesser.exs

defmodule Guesser do
  def guess(actual, range) do
    range_midpoint = midpoint(range)
    try_guess(range_midpoint, actual, range)
  end

  defp try_guess(range_midpoint, actual, range) do
    IO.puts "trying #{range_midpoint}"

    cond do
      range_midpoint == actual ->
        IO.puts range_midpoint
      range_midpoint > actual ->
        first .. _last = range
        guess(actual, first .. range_midpoint)
      range_midpoint < actual ->
        _first .. last = range
        guess(actual, range_midpoint .. last)
    end
  end

  defp midpoint(range) do
    first..last = range
    div(first + last, 2)
  end
end