private static void postOrder(Node node1) {
		Stack<Node> nodes= new Stack<>();
		Node prevVistedNode=null;
		Node tempNode= node1;
		while(true) {
			while(tempNode!=null && tempNode!=prevVistedNode) {
				nodes.push(tempNode);
				tempNode=tempNode.left;
			}
			tempNode=nodes.pop();
			System.out.println(tempNode.data);
			prevVistedNode=tempNode;
			if(nodes.empty()) {break;}
			if(nodes.peek()!=null && nodes.peek().right!=null) {
				tempNode=nodes.peek().right;
			}
		}
	}