链表 泛型链表

 链表

class Program
    {
        static void Main(string[] args)
        {
　　　　　　　　//当然 这里 还可以加 string 等 其他类型
            LinkedList<int> li = new LinkedList<int>();
        
            for (int i = 0; i < 10; i++)
            {
                li.AddFirst(i);
                
            }
            LinkedList list = new LinkedList();
            list.AddFirst(4);
            list.AddFirst(50);
            list.AddFirst(3);
            foreach (var i in li)
            {
                Console.WriteLine(i);
            }
            Console.ReadLine();
        }
    }

    public class LinkedList :IEnumerable
    {
        private LinkedListNode first;
        public LinkedListNode First
        {
            get { return first; }
        }
        private LinkedListNode last;
        public LinkedListNode Last
        {
            get { return last; }
        }

        public LinkedListNode AddFirst(T node)
        {
            LinkedListNode newNode = new  LinkedListNode(node);
            if (first==null)
            {
                first = newNode;
                last = first;
            }
            else
            {
                last.Next = newNode;
                last = newNode;
            }
            return newNode;
        }
        public IEnumerator GetEnumerator()
        {
            LinkedListNode curr = first;
            while (curr!=null)
            {
                yield return curr.Value;
                curr  = curr.Next;
            }

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

    /// 泛型 LinkListNode
    /// 
    /// 
    public class LinkedListNode
    {
        private T value;
        public  LinkedListNode(T  value)
        {
            this.value =value;
        }
        public T Value
        {
            get { return value; }
        }
        private LinkedListNode next;
        public LinkedListNode Next
        {
            get { return next; }
            internal set { next = value; }
        }
        private LinkedListNode prev;
        public LinkedListNode Prev
        {
            get { return prev; }
            internal set { prev = value; }
        }
    }
    /// 

    ///  
    /// 
    public class LinkedList
    {
        private LinkedListNode first;
        public LinkedListNode First
        {
            get { return first; }
           
        }
        private LinkedListNode last;
        public LinkedListNode Last
        {
            get { return last; }
        }
        public LinkedListNode AddFirst(object val)
        {
            LinkedListNode node =  new  LinkedListNode(val);
            //链表的头 是空的 把这个节点 放在头部，
            // 否则放在尾部 把 链表的最后一个变成这个节点
            if (first==null)
            {
                first = node;
                last = first;
            }
            else
            {
                last.Next = node;
                last = node;
            }
            return node;
        }

        public IEnumerator GetEnumerator()
        {
            LinkedListNode curr = first;
            while (curr != null)
            {
                yield return curr.Value;
                curr = curr.Next;
            }
        } 
    }
    public class LinkedListNode
    {
        private object value;
        public LinkedListNode(object val)
        {
            this.value = val;
        }
        public object Value
        {
            get { return value; }
        }
        private LinkedListNode next;
        public LinkedListNode Next
        {
            get { return next; }
            internal set { next = value; }
        }
        private LinkedListNode prev;

        public LinkedListNode Prev
        {
            get { return prev; }
            internal set { prev = value; }
        }
    }