//
// program to count down from n to 0 (print numbers from n to 0)
//

// function to do the counting
def countdown(n : Int) {
  if (n > 0) {
    // reverse the next two statements to count up
    println(n)
    countdown(n-1)
  }
  else {
    println(n)
  }
}

// main program -- prompt for input and call function
println("enter the starting number (>= 0):")
val num = readInt
if (num < 0) {
  println("too small!")
}
else {
  countdown(num)
}