e7.2-1.rb

学习ruby比较好的入门教材,可以

#E7.2-1.rb  

module Me

  def sqrt(num, rx=1, e=1e-10)
    num*=1.0
	  (num - rx*rx).abs <e ?	rx :	sqrt(num, (num/rx + rx)/2, e)	
  end

end

include Math
puts   sqrt(293)
#puts   sqrt(293, 5, 0.01)

include Me
puts   sqrt(293)
puts   sqrt(293, 5, 0.01)