Square Roots by Newton's Method

sqrt.ex

defmodule Sqrt do

  def sqrtiter(guess, x) do
    if (goodenought?(guess, x)) do
      guess
    else
       guess
       |> improve(x)
       |> sqrtiter(x)
    end
  end

  def goodenought?(guess, x) do
    guess
    |> square
    |> Kernel.-(x)
    |> abs()
    |> Kernel.<(0.001)
  end

  def improve(guess, x), do: average(guess, x / guess)
  def average(x, y), do: (x + y) / 2
  def square(x), do: x * x

end

Sqrt.sqrtiter(1, 2) |> IO.puts()