convert(1999)

def convert(num: Int): Unit = {
  val l = toList(num)
  toRomanNumerals(l)
  println()
  println()
}

def toRomanNumerals(nums : List[Int]): Unit ={
  if(nums.nonEmpty){
    print(toRomanNumeral(nums.length-1 , nums.head))
    toRomanNumerals(nums.tail)
  }
}

def toRomanNumeral(tens: Int, digit: Int): String = {
  val (bot, middle, top) =
    if (tens == 0)
      ("I", "V", "X")
    else if (tens == 1)
      ("X", "L", "C")
    else if(tens == 2)
      ("C", "D", "M")
    else if(tens == 3)
      ("M", "?", "??")

  digit match{
    case 1 => s"$bot"
    case 2 => s"$bot$bot"
    case 3 => s"$bot$bot$bot"
    case 4 => s"$bot$middle"
    case 5 => s"$middle"
    case 6 => s"$middle$bot"
    case 7 => s"$middle$bot$bot"
    case 8 => s"$middle$bot$bot$bot"
    case 9 => s"$bot$top"
    case _ => ""
  }
}

def toList(num: Int): List[Int] = {
  num.toString.map(_.toString.toInt).toList
}