arr

scala
object W72 {
  def main(args: Array[String]): Unit = {
    val arr1 = Array(1, 2, 3)
    println(arr1(0))
    println(arr1(2))
    println(arr1(20))
  }
}



scala
object W71 {
  def main(args: Array[String]): Unit = {
    val arr1 = scala.collection.mutable.ArrayBuffer(1,2,3)
    arr1 += 4
    println(arr1)
    val arr2 = Array(1,2,3)
    println(arr2)


  }
}