Solution Review: Finding Ancestors of a Given Node in a BST

using System;
namespace chapter_6
{
    class Solution
    {
        //Helper Recursive Function to find ancestors of k node
        //and add them to the result string
        static bool recur(Node rootNode, int k, ref string result)
        {
            //base cases
            if (rootNode == null)
                return false;
            else if (rootNode.value == k)
                return true;
            else
            {
                //To check if target is present in either left or right subtree of currentNode
                if (recur(rootNode.leftChild, k, ref result) || recur(rootNode.rightChild, k, ref result))
                {
                    result = result + rootNode.value.ToString() + " ";
                    return true;
                }
            }
            return false;
        }
        static string findAncestors(Node rootNode, int k)
        {
            string result = string.Empty;
            recur(rootNode, k, ref result);
            return result;
        }
        static void Main(string[] args)
        {
            BinarySearchTree BST = new BinarySearchTree(6);
            BST.insertBST(1);
            BST.insertBST(133);
            BST.insertBST(12);
            Console.WriteLine(findAncestors(BST.getRoot(), 12));
        }
    }
}