/* 
 * BinTree.java 
 * Simple implementation of binary trees in Java.
 *
 * Author:    David Aspinall
 * Copyright: University of Edinburgh, 2001.
 *
 * BinTree.java,v 1.5 2002/11/29 13:59:44 da Exp
 *
 */

class BinTree {
    private BinTree left;	  // left subtree
    private Object  data;	  // label for node
    private BinTree right;	  // right subtree

    // Construct a leaf given a label.
    BinTree(Object data) {
	this.data = data;
	// left and right default to null (the empty tree)
    }

    // Construct a tree given a label and two subtrees.  
    BinTree(BinTree left, Object data, BinTree right) {
	this.data = data;
	this.left = left;
	this.right = right;
    }

    public void printNodesPreorder() {
	printNodesPreorder(this);
    }
    private static void printNodesPreorder(BinTree tree) {
	if (tree != null) {
	    System.out.print(tree.data);
	    System.out.print(" ");
	    printNodesPreorder(tree.left);
	    printNodesPreorder(tree.right);
	}
    }
}