import java.util.Stack;

class Node implements Comparable<Node> {
	public Node left;
	public int data;
	public Node right;

	public Node(int val)
	{
		this.data=val;
	}

	@Override
	public int compareTo(Node that) {
		return this.data - that.data ;
	}

	@Override
	public String toString(){
		return this.data + "";
	}
}
/**
 * Iterative Inorder Traversal Using Stack
 * @author PRATEEK
 *
 */
class IterativeInorder {

	public static void main(String[] args) {
		Node root = new Node(12);
		root.left = new Node(8);
		root.left.left = new Node(6);
		root.left.right = new Node(10);

		root.right = new Node(16);
		root.right.left = new Node(14);
		root.right.right = new Node(20);

		IterativeInorder obj = new IterativeInorder();
		obj.iterativeInorder(root);
	}

	/**
	 * Iterative Inorder Traversal using Stack
	 * @param node
	 */
	public void iterativeInorder(Node node) 
	{
		Stack<Node> stack = new Stack<Node>();
		for (;;) 
		{
			if (node != null) 
			{
				stack.push(node);
				node = node.left;
			}
			else 
			{
				if (!stack.isEmpty()) 
				{
					node = stack.pop();
					System.out.print(node + "\t");
					node = node.right;
				}
				else
					break;
			}
		}
	}
}