C# 实现简单的迭代器模式

// 迭代器接口
public interface IIterator<T>
{
    bool HasNext();
    T Next();
}
// 聚合接口
public interface IAggregate<T>
{
    IIterator<T> CreateIterator();
}
// 具体聚合类
public class MyCollection<T> : IAggregate<T>
{
    private readonly List<T> _items = new List<T>();
    public void Add(T item) => _items.Add(item);
    public T Get(int index) => _items[index];
    public int Count => _items.Count;
    public IIterator<T> CreateIterator()
    {
        return new MyIterator<T>(this);
    }
}
// 具体迭代器类
public class MyIterator<T> : IIterator<T>
{
    private readonly MyCollection<T> _collection;
    private int _index = 0;
    public MyIterator(MyCollection<T> collection) => _collection = collection;
    public bool HasNext() => _index < _collection.Count;
    public T Next() => _collection.Get(_index++);
}
// 调用示例
public static void TestIterator()
{
    var collection = new MyCollection<string>();
    collection.Add("A");
    collection.Add("B");
    collection.Add("C");
    var iterator = collection.CreateIterator();
    while (iterator.HasNext())
    {
        Console.WriteLine("元素: " + iterator.Next());
    }
}