stap.scala

import scala.util.Random

object Main {

  def main(args:Array[String]) = {
    findSTAP()
  }

  def findSTAP():Unit = 
    randomString(4) match {
      case "STAP" => 
        println("STAP細胞")
        println("見つかったよ!")
      case other => 
        print(other + "細胞")
        findSTAP()
    }

  def randomString(letterLength:Int):String = {
    val r = new Random()
    letterLength match {
      case 0 => ""
      case 1 => int2String(r.nextInt(25))
      case n => int2String(r.nextInt(25)) + randomSTAP( n - 1)
    }
  }

    val int2String:PartialFunction[Int,String] = {
      case  0 => "A"
      case  1 => "B"
      case  2 => "C"
      case  3 => "D"
      case  4 => "E"
      case  5 => "F"
      case  6 => "G"
      case  7 => "H"
      case  8 => "I"
      case  9 => "J"
      case 10 => "K"
      case 11 => "L"
      case 12 => "M"
      case 13 => "N"
      case 14 => "O"
      case 15 => "P"
      case 16 => "Q"
      case 17 => "R"
      case 18 => "S"
      case 19 => "T"
      case 20 => "U"
      case 21 => "V"
      case 22 => "W"
      case 23 => "X"
      case 24 => "Y"
      case 25 => "Z"
  }

}