public class TreeTest { public static void main(String[] args) { // let's encode 1 - 2^4 x 2 // (- 1 (* (^ 2 4) 2)) BinaryTreeNode root = new BinaryTreeNode<>("-"); System.out.println(root.getHeight()); root.setLeft(new BinaryTreeNode<>("1")); root.setRight(new BinaryTreeNode<>("*")); root.getRight().setLeft(new BinaryTreeNode<>("^")); root.getRight().setRight(new BinaryTreeNode<>("2")); root.getRight().getLeft().setLeft(new BinaryTreeNode<>("2")); root.getRight().getLeft().setRight(new BinaryTreeNode<>("4")); System.out.println(root); System.out.println(root.size()); System.out.println(BinaryTreeNode.getHeight(root)); } }