        static void Main(string[] args)
        {
            Tree tree = new Tree();
            int insertValue;
            Console.WriteLine("Inserting values: ");
            Random random = new Random();
            // insert 10 random integers from 0-99 in tree 
            for (int i = 1; i <= 10; i++)
            {
                insertValue = random.Next(100);
                Console.Write(insertValue + " ");
                tree.InsertNode(insertValue);
            } // end for
            // perform preorder traversal of tree
            Console.WriteLine("\n\nPreorder traversal");
            tree.PreorderTraversal();
            // perform inorder traversal of tree
            Console.WriteLine("\n\nInorder traversal");
            tree.InorderTraversal();
            // perform postorder traversal of tree
            Console.WriteLine("\n\nPostorder traversal");
            tree.PostorderTraversal();
            Console.Read();
        } // end method Main
