bst pre/post order

void iterativePreorder()
    {
        iterativePreorder(root);
    }

    // An iterative process to print preorder traversal of Binary tree
    void iterativePreorder(Node node) {

        // Base Case
        if (node == null) {
            return;
        }

        // Create an empty stack and push root to it
        Stack<Node> nodeStack = new Stack<Node>();
        nodeStack.push(root);

        /* Pop all items one by one. Do following for every popped item
         a) print it
         b) push its right child
         c) push its left child
         Note that right child is pushed first so that left is processed first */
        while (nodeStack.empty() == false) {

            // Pop the top item from stack and print it
            Node mynode = nodeStack.peek();
            System.out.println(mynode.info);
            nodeStack.pop();

            // Push right and left children of the popped node to stack
            if (mynode.right != null) {
                nodeStack.push(mynode.right);
            }
            if (mynode.left != null) {
                nodeStack.push(mynode.left);
            }
        }
    }

    void itPost()
    {
        if (root==null) return;

        Stack<Node> s1= new Stack<>();
        Stack<Node> s2= new Stack<>();

        s1.push(root);

        while(!s1.isEmpty())
        {
            Node temp=s1.pop();
            s2.push(temp);

            if (temp.left != null) {
                s1.push(temp.left);
            }
            if (temp.right != null) {
                s1.push(temp.right);
            }
        }
        while(!s2.isEmpty())
        {
            Node temp=s2.pop();
            System.out.println(temp.info);
        }
    }