//
// simple demo of using recursive functions to operate on arrays
//
println("how many values?")
val n = readInt
val a = new Array[Int](n)

fillArray(a, 0)

println("you entered:")
printArray(a, 0)

println("sum is " + sumArray(a, 0))
println("product is " + productArray(a, 0))

def fillArray(aa : Array[Int], startIndex : Int) {
  if (startIndex < aa.length) {
    println("next value?")
    val n = readInt
    aa(startIndex) = n
    fillArray(aa, startIndex + 1)
  }
}

def printArray(aa : Array[Int], startIndex : Int) {
  if (startIndex < aa.length) {
    println(aa(startIndex))
    printArray(aa, startIndex + 1)
  }
}

def sumArray(aa : Array[Int], startIndex : Int) : Int = {
  if (startIndex < aa.length) {
    aa(startIndex) + sumArray(aa, startIndex + 1)
  }
  else {
    0
  }
}

def productArray(aa : Array[Int], startIndex : Int) : Int = {
  if (startIndex < aa.length) {
    aa(startIndex) * productArray(aa, startIndex + 1)
  }
  else {
    1
  }
}