static void Main(string[] args) { BinarySearchTree<int> tree = new BinarySearchTree<int>(); tree.Insert(9); tree.Insert(7); tree.Insert(15); tree.Insert(6); tree.Insert(8); tree.Insert(10); tree.Insert(20); tree.Insert(21); tree.Insert(19); tree.PrintDFS(); Console.WriteLine("Remove 15"); tree.Remove(15); tree.PrintDFS(); }