import scala.math.sqrt

object StddevCalc extends App {

  def calcAvgAndStddev[T](ts: Iterable[T])(implicit num: Fractional[T]): (T, Double) = {
    def avg(ts: Iterable[T])(implicit num: Fractional[T]): T =
      num.div(ts.sum, num.fromInt(ts.size)) // Leaving with type of function T

    val mean: T = avg(ts) // Leave val type of T
    // Root of mean diffs
    val stdDev = sqrt(ts.map { x =>
      val diff = num.toDouble(num.minus(x, mean))
      diff * diff
    }.sum / ts.size)

    (mean, stdDev)
  }

  println(calcAvgAndStddev(List(2.0E0, 4.0, 4, 4, 5, 5, 7, 9)))
  println(calcAvgAndStddev(Set(1.0, 2, 3, 4)))
  println(calcAvgAndStddev(0.1 to 1.1 by 0.05))
  println(calcAvgAndStddev(List(BigDecimal(120), BigDecimal(1200))))

  println(s"Successfully completed without errors. [total ${scala.compat.Platform.currentTime - executionStart}ms]")

}