public class SearchTree<E extends Comparable<E>> {
    private SearchTreeNode<E> overallRoot;

    // post: constructs an empty tree
    public SearchTree() {
        overallRoot = null;
    }

    // pre: tree satisfies the binary search tree property
    // post: value is added to overall tree so as to preserve the
    //       binary search tree property
    public void add(E value) {
        overallRoot = add(overallRoot, value);
    }
    
    // post: value is added to given tree so as to preserve the
    //       binary search tree property
    private SearchTreeNode<E> add(SearchTreeNode<E> root, E value) {
        if (root == null) {
            root = new SearchTreeNode<E>(value);
        } else if (value.compareTo(root.data) <= 0) {
            root.left = add(root.left, value);
        } else {
            root.right = add(root.right, value);
        }
        return root;
    }

    // post: prints the data of the tree, one per line
    public void print() {
        System.out.print("preorder:");
        printInorder(overallRoot);
        System.out.println();
    }
    
    // post: prints in inorder the tree with given root
    private void printInorder(SearchTreeNode<E> root) {
        if (root != null) {
            printInorder(root.left);
            System.out.print(" " + root.data);
            printInorder(root.right);
        }
    }
}