static void Main(string[] args)
{
//客户端代码可能不知道具体的Iterator或Collection类，这取决于要在程序中保留的间接级别。
var collection = new WordsCollection();
collection.AddItem("first item");
collection.AddItem("second item");
collection.AddItem("third item");
Console.WriteLine("Straight traversal:");
foreach (var item in collection)
{
Console.WriteLine(item);
}
collection.ReverseDirection();
Console.WriteLine();
Console.WriteLine("reverse traversal:");
foreach (var item in collection)
{
Console.WriteLine(item);
}
Console.ReadKey();
}
public AlphabeticalOrderIterator(WordsCollection collection, bool reverse)
{
_collection = collection;
_reverse = reverse;
if (reverse)
{
_postsion = collection.GetItems().Count;
}
}