在Scala中递归计算平方根

def sqrt(x: Double): Double = {
  def sqrtIter(guess: Double): Double = {
    if (isGoodEnough(guess)) guess
    else sqrtIter(improve(guess))
  }

  def isGoodEnough(guess: Double): Boolean = {
    Math.abs(guess * guess - x) / x < 0.0001
  }

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

  sqrtIter(1.0)
}

val result = sqrt(16.0)
println(result)  // 输出：4.0