/** Let's make a tree, and print it out.
 *  There are 2 constructors we can call -- we can create a tree with a
 *  single node, or with 2 existing trees and a new node , we can make a 
 *  bigger tree.
 */
import java.util.*;

public class Driver
{
  public static void main(String [] args)
  {
    Tree one = new Tree(new Item("1"));
    Tree two = new Tree(new Item("2"));
    Tree three = new Tree(new Item("3"));
    Tree four = new Tree(new Item("4"));
    Tree difference = new Tree(new Item("-"), one, two);
    Tree product = new Tree(new Item("*"), three, four);
    Tree sum = new Tree(new Item("+"), difference, product);

    // default printout (preorder shown vertically)
    System.out.println(sum);

    // 3 traversals
    // When we traverse, we need to remember to call getData because
    // the node itself does not have toString.  We're only interested in
    // seeing the data (string) within.
    Iterator preorder = sum.preorderIterator();

    /* not implemented yet
    Iterator inorder = sum.inorderIterator();
    Iterator postorder = sum.postorderIterator();
    */

    System.out.print("Preorder:   ");
    while (preorder.hasNext())
      System.out.print(((Node) preorder.next()).getData() + " ");

    /* not implemented yet
    System.out.print("\nInorder:    ");
    while (inorder.hasNext())
      System.out.print(((Node) inorder.next()).getData() + " ");
    System.out.print("\nPostorder:  ");
    while (postorder.hasNext())
      System.out.print(((Node) postorder.next()).getData() + " ");
    System.out.println();
    */

  }
}