static void Main(string[] args) { BinaryTree binaryTree = new BinaryTree(); binaryTree.Insert(12); binaryTree.Insert(3); binaryTree.Insert(15); binaryTree.Insert(6); binaryTree.Insert(9); binaryTree.Insert(21); binaryTree.Display(); Console.WriteLine("\nBinary Tree Count = {0}", binaryTree.Count()); Console.ReadLine(); }