object Haller extends Student with Person with Sex {
  val name = "Olaf Haller"
  var addr = ""
  val matr = 123456
  val male = true

  import util._
  def inLecture = Random.nextBoolean

  override def toString = "Haller(" + name + (if(male) ", m" else ", w") + ", " + matr + ", Studiert" + (if(inLecture) ")" else " nicht)")
}