Square root

square_root.rb

def sqrt(num, precision, beg=0, final=num)
  final = 1 if num < 1 # handle cases where the squareroot is > num i.e. sqrt(0.1) ~ 0.3

  begin
    guess = (beg + final) / 2.0
    diff = num - (guess ** 2)

    if diff.abs <= precision
      return guess
    elsif diff > 0
      beg = guess
    else
      final = guess
    end
  end while diff.abs > precision
end

def test(num, precision)
  my_sqrt = sqrt(num, precision)
  diff = num - (my_sqrt ** 2)
  puts "num: #{num}, precision: #{precision}, pass? #{diff.abs <= precision}"
end

test(0, 0.0001)
test(0.4, 0.0001)
test(1, 0.0001)
test(8, 0.0001)