static void Main(string[] args)
{
ITree tree = new BinarySearchTree();
Console.WriteLine(tree.ToString());
tree.Add(0);
Console.WriteLine(tree.ToString());
tree.Add(1);
Console.WriteLine(tree.ToString());
/*tree.Add(2);
* tree.Add(3);
* tree.Add(4);
* tree.Add(5);
* tree.Add(6);
* Console.WriteLine(tree.ToString());*/
}