Quick sort algorithm in scala

Application.scala

object Application extends App {

  def quickSort(l: Array[Int], low: Int, high: Int): Unit = {
    if (low < high) {
      val pivotIdx = partition(l, low, high)
      quickSort(l, low, pivotIdx - 1)
      quickSort(l, pivotIdx + 1, high)
    }
  }

  def partition(arr: Array[Int], low: Int, high: Int): Int = {
    // pivot
    val pivot = arr(high)
    // Index of smaller element and
    // indicates the right position
    // of pivot found so far
    var i = low - 1
    for (j <- low until high) {
      // If current element is smaller
      // than the pivot
      if (arr(j) < pivot) {
        // Increment index of
        // smaller element
        i += 1
        swap(arr, i, j)
      }
    }
    swap(arr, i + 1, high)

    i + 1
  }

  def swap(arr: Array[Int], i: Int, j: Int): Unit = {
    val temp = arr(i)
    arr(i) = arr(j)
    arr(j) = temp
  }

  val arr = Array(10, 7, 8, 9, 1, 5)
  quickSort(arr, 0, arr.length - 1)

  arr.foreach(println)

}