class Main {
	public static void main(String[] args){
		// 构造了一个空树
		BinaryTree<Integer> bt = new BinaryTree<Integer>();
	/*
	*        10
	*     5      15
	*   3   7  12   20
	* preOrder: 10 5 3 7 15 12 20
	*/		
		bt.root = new Node<Integer>(10);
		Node<Integer> left1 = new Node<Integer>(5);
		bt.root.left = left1;
		Node<Integer> right1 = new Node<Integer>(15);
		bt.root.right = right1;

		Node<Integer> left21 = new Node<Integer>(3);
		left1.left = left21;
		Node<Integer> left22 = new Node<Integer>(7);
		left1.right = left22;

		Node<Integer> left23 = new Node<Integer>(12);
		Node<Integer> left24 = new Node<Integer>(20);
		right1.left = left23;
		right1.right = left24;

		bt.preOrder();
	}
}