/**  an DeptDirectory is either:
 *   (i)  the empty directory new Empty(), or
 *   (ii) the non-empty directory new Cons(Entry,DeptDirectory)
 */
abstract class DeptDirectory {}

class Empty extends DeptDirectory {
  public String toString() { return("");}
}

class Cons extends DeptDirectory {
  Entry first;
  DeptDirectory rest;

  /* constructor */
  Cons(Entry f, DeptDirectory r) {
    this.first = f;
    this.rest = r;
  }

  /* accessors */
  Entry getFirst() { return this.first; }
  DeptDirectory getRest() { return this.rest; } 
  public String toString() { return(first.toString() + " " + rest.toString());}
}


class TestClass  {
  public void test() {
    DeptDirectory d = new Cons(new Entry("Corky","DH3104","x 6042"), 
             new Cons(new Entry("Matthias","DH3106","x 5732"), new Empty()));
      System.out.println(d);
  }

}