IT工程師數位筆記本

// 抽象聚合類
    public interface IListCollection
    {
        Iterator GetIterator();
    }

    // 迭代器抽象類
    public interface Iterator
    {
        bool MoveNext();
        Object GetCurrent();
        void Next();
        void Reset();
    }

    // 具體聚合類
    public class ConcreteList : IListCollection
    {
        int[] collection;
        public ConcreteList()
        {
            collection = new int[] { 2, 4, 6, 8 };
        }

        public Iterator GetIterator()
        {
            return new ConcreteIterator(this);
        }

        public int Length
        {
            get { return collection.Length; }
        }

        public int GetElement(int index)
        {
            return collection[index];
        }
    }

    // 具體迭代器類
    public class ConcreteIterator : Iterator
    {
        // 迭代器要集合對象進行遍歷操作，自然就需要引用集合對象
        private ConcreteList _list;
        private int _index;

        public ConcreteIterator(ConcreteList list)
        {
            _list = list;
            _index = 0;
        }


        public bool MoveNext()
        {
            if (_index < _list.Length)
            {
                return true;
            }
            return false;
        }

        public Object GetCurrent()
        {
            return _list.GetElement(_index);
        }

        public void Reset()
        {
            _index = 0;
        }

        public void Next()
        {
            if (_index < _list.Length)
            {
                _index++;
            }
                
        }
    }

    // 客戶端
    class Program
    {
        static void Main(string[] args)
        {
            Iterator iterator;
            IListCollection list = new ConcreteList();
            iterator = list.GetIterator();

            while (iterator.MoveNext())
            {
                int i = (int)iterator.GetCurrent();
                Console.WriteLine(i.ToString());
                iterator.Next();
            }

            Console.Read();
        }
    }