C#: iterator

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using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;


namespace test
{

    public class Node<T>
    {
        public T Value { get; private set; }
        public Node<T> Next { get; internal set; }
        public Node<T> Pre { get; internal set; }


        public Node(T value)
        {
            this.Value = value;
        }
    }


    class TheList<T>:IEnumerable<T>
    {
        public Node<T> First { get; private set; }
        public Node<T> Last { get; private set; }

        public void AddLast(T value)
        {
            Node<T> newNode = new Node<T>(value);

            if (this.First == null)
            {
                this.First = newNode;
                newNode.Pre = this.Last;
                this.Last = this.First;

            }
            else
            {
                Node<T> pervious = this.Last;
                this.Last.Next = newNode;
                this.Last = newNode;
                this.Last.Pre = pervious;
            }
        }

        IEnumerator IEnumerable.GetEnumerator()
        {
            return GetEnumerator();
        }

        public IEnumerator<T> GetEnumerator()
        {
            Node<T> current = this.First;

            while (current != null)
            {
                yield return current.Value;
                current = current.Next;
            }
        }

    }


    class Program
    {

        public static void Main(string[] args)
        {

            TheList<int> list = new TheList<int>();
            list.AddLast(10);
            list.AddLast(20);
            list.AddLast(30);

            foreach(int val in list)
            {
                Console.WriteLine(val);
            }

            return;
        }
    };
}

 

 

c# iterator原理:

using System;
using System.Collections.Generic;
using System.Collections;
using System.Linq;
using System.Text;
using System.Threading.Tasks;


namespace test
{

    class Enumerator :
        System.Collections.Generic.IEnumerator<string>, 
        System.Collections.IEnumerator, 
        System.IDisposable
    {
        private int state_;
        private string current_;

        public Enumerator(int state = 0)
        {
            this.state_ = state;
        }

        bool System.Collections.IEnumerator.MoveNext()
        {

            Console.WriteLine("move next");
            switch (this.state_)
            {
                case 0:
                    {
                        this.current_ = "hello";
                        this.state_ = 1;
                        return true;
                    }
                case 1:
                    {
                        this.current_ = "word";
                        this.state_ = 2;
                        return true;
                    }
                case 2:
                    break;
            }

            return false;
        }

        void System.Collections.IEnumerator.Reset()
        {
            Console.WriteLine("throw");
            throw new NotSupportedException();
        }

        string System.Collections.Generic.IEnumerator<string>.Current
        {
            get
            {
                Console.WriteLine("--------------------");
                return this.current_;
            }
        }

        object System.Collections.IEnumerator.Current
        {
            get
            {
                Console.WriteLine("get Current");
                return this.current_;
            }
        }


        void IDisposable.Dispose()
        {
            Console.WriteLine("stop");
            return;
        }

    }

    class TheIterator
    {
        public IEnumerator GetEnumerator()
        {
            return new Enumerator();
        }
    }


    class test
    {
        public static void Main(string[] args)
        {
            TheIterator itr = new TheIterator();

            foreach(var val in itr)
            {
                Console.WriteLine(val);
            }


            return;

        }
    }
    
}

 

 

转载于:https://my.oschina.net/SHIHUAMarryMe/blog/884031