//       CS210 - Algorithms and Data Structures I

//            Department of Computer Science

//       National University of Ireland, Maynooth

//

//        Extra material in preparation for CS211

//                     Tom Naughton

//                    December 2000

//

//---------------------------------------------------------

//http://www.cs.may.ie/~tnaughton/cs210/

//=========================================================



// Examples of recursive implementations of linked-list

// methods that you should be familiar with.





//

// A print method

//

  public void print() {

    /* Prints the entire list from the head.

    */

    System.out.print("List:");

    printRec(head);

    System.out.println();

  }

  private void printRec(Node n) {

    /* Private recursive method that does all the work

    ** for print().

    */

    if (n != null) {

      System.out.print(n.getData().toString() + ',');

      printRec(n.getNext());

    }

  }





//

// A method to print in reverse

//

  public boolean contains(Object o) {

    /* Return true if o is in the list.

    */

    return containsRec(head, o);

  }

  private boolean containsRec(Node n, Object o) {

    /* Private recirsive method that does all the work

    ** for contains(o). It returns true at the first

    ** encounter with o, and returns false if it ever

    ** reaches the end of the list.

    */

    if (n == null) {

      return false;



    } else if (n.getData().equals(o)) {

      return true;



    } else {

      return containsRec(n.getNext(), o);

    }

  }





//

// A method to print in reverse

//

  public void printInReverse() {

    /* Prints the entire list from the head.

    */

    System.out.print("List:");

    printInReverseRec(head);

    System.out.println();

  }

  private void printInReverseRec(Node n) {

    /* Private recursive method that does all the work

    ** for printReverse().

    */

    if (n != null) {

      printRec(n.getNext());

      System.out.print(n.getData().toString() + ',');

    }

  }