Imperative style guessing game in Scala

Here’s a simple guessing game program using Scala’s imperative style and not functional style.

class GuessingGame{
	private var target:Int = (Math.random()*100).asInstanceOf[Int]
	var attempts:Int = 0
	var message:String = ""
	var gameOver:Boolean = false
	def play(guess:Int):Unit= {
		attempts += 1
		if(guess < target)
			message = "Aim Higher"
		else if(guess > target)
			message = "Aim Lower"
		else{
			message = "You've got it!!!"
			gameOver = true
		}
	}	
}
val game = new GuessingGame
println("Enter a number between 1 and 100")
while(!game.gameOver){
	var guess:Int = readLine().toInt
	game.play(guess)
	println(game.message)
}