Compile and Execute Scala Online

object HelloWorld {
   def main(args: Array[String]) {
      val l = List(1,2,3,4)
      val x = l.:+(6)
      val y = List(9) :: x
      println(y.getClass())
      
       val mainList = List(3, 2, 1)
 val with4 =    4 :: mainList  // re-uses mainList, costs one :: instance
 val with42 =   42 :: mainList // also re-uses mainList, cost one :: instance
 val shorter =  mainList.head  // costs nothing as it uses the same 2::1::Nil instances as mainList
 println(shorter)

 println("---------------")
 
    val a = List(1,2,3,4)
    val b = (5 /: a)(_*_)
    val c = (a :\ 5)(_*_)
    println(b + " " + c)
    
 println("-------------- copy to array example")
    
    
   }
}