Excercise 2.2

test.scala

// implement isSorted, which checks whether an Array[A] is sorted according to a given comparison function:
// def isSorted[A] (as: Array[A], ordered: (A, A) => Boolean): Boolean

object Test {
  def isSorted[A](as: Array[A], ordered: (A, A) => Boolean): Boolean = {
    def loop(n: Int): Boolean =
      if (n+1 >= as.length) true
      else if (!ordered(as(n), as(n+1))) false
      else loop(n+1)

    loop(0)
  }

  def ordered[A](a: A, b: A): Boolean = {
    a < b
  }

  def main(args: Array[String]): Unit = {
    val result = isSorted(Array(1,2,3,5,4), ordered)

    println(result)
  }
}