*/
public class Node  {

    final int contents;
  Node left, right;
    Node parent;
  Boolean available = true;
    Node(int contents, Node left, Node right) {
        this.contents = contents;
        this.left = left;
        if (left != null) {
            left.parent = this;
        }
        this.right = right;
        if (right != null) {
            right.parent = this;
        }
    }
    public Node copy(){
        return new Node(this.contents,this.left,this.right);
    }



  public CustomIterator preorderIterator() {
      PreOrderIterator node=new PreOrderIterator(this);
      return node;
  }

  public CustomIterator inorderIterator(){
       InOrderIterator node=new InOrderIterator(this);
      return node;
  }

  public CustomIterator postorderIterator(){
        PostOrderIterator node=new PostOrderIterator(this);
      return node;
  }
}