sqrt

package week1

import java.lang.Math._

object session {

  def sqrt(x: Double) = {
    def sqrtItr(guess: Double, x:Double): Double =
      if (isGoodEnough(guess)) guess
      else (sqrtItr(improve(guess),x))

    def isGoodEnough(guess: Double) =
      abs(guess * guess - x) / x < 0.0001

    def improve(guess: Double) =
      (guess + x / guess) / 2

    sqrtItr(1.0, x)
  }                                               //> sqrt: (x: Double)Double

  sqrt(1e-6)                                      //> res0: Double = 0.0010000001533016628
  sqrt(1e60)                                      //> res1: Double = 1.0000000031080746E30
}