package ex05.task2

trait SedcSet [+A] {

  def + [B >: A] (item: B): SedcSet [B]

  def - [B >: A] (item: B): SedcSet [B]

  def size(): Int

  def contains [B >: A] (item: B): Boolean

  override def equals(obj: Any /*Any is correct as parameter to equals, do not modify*/): Boolean

  override def hashCode(): Int

  def print(printer: Printer [A]): Unit

  def foreach [B] (f: A => B): Unit

}

object SedcSet {
  def apply[A](xs: A*): SedcSet [A]  = EmptySedcSet
}


object EmptySedcSet extends SedcSet[Nothing]  {

  override def + [A >: Nothing] (item: A): SedcSet [A] = ???

  override def -[B >: Nothing](item: B): SedcSet[B] = ???

  override def size(): Int = ???

  override def contains[B >: Nothing](item: B): Boolean = ???

  override def print(printer: Printer [Nothing]): Unit = ???

  override def foreach[B](f: Nothing => B): Unit = ()

}

trait Printer [-A] {

  def print(a: A):Unit
}


object Main {
  // You may use any Java/ Scala standard collection inside this object
  def main(args: Array[String]): Unit = {

  }
}