线性表的链式存储——单链表

        public interface IListliner<T>
    {
        T GetElement(int i);
        void Insert(T t, int i);
        void Add(T t);
        void Delete(int i);
        //获取线性表长度
        int GetLength();
        bool IsEmpty();
        int LocationElement(T t);
        void Clear();
        void Reverse();
    }
    /// <summary>
    /// 链表节点类型
    /// </summary>
    /// <typeparam name="T"></typeparam>
    class Node<T>
    {
        /// <summary>
        /// 数据
        /// </summary>
        private T tdata;
        public T Data
        {
            get { return this.tdata; }
            set { this.tdata = value; }
        }
        /// <summary>
        /// 节点位置
        /// </summary>
        private Node<T> nNext;
        public Node<T> Next
        {
            get { return this.nNext; }
            set { this.nNext = value; }
        }
        public Node()
        {
            this.tdata = default(T);
            this.nNext = null;
        }
        public Node(T t)
        {
            this.tdata = t;
            this.nNext = null;
        }
        public Node(T t, Node<T> node)
        {
            this.tdata = t;
            this.nNext = node;
        }
    }
    /// <summary>
    /// 表示链表添加元素的位置：头部和尾部
    /// </summary>
    enum AddPosition
    {
        Head,
        Tail
    }

    /// <summary>
    /// 单链表类
    /// </summary>
    /// <typeparam name="T"></typeparam>
    class Linkedlist<T> : IListliner<T>
    {
        //链表头部
        private Node<T> tHead;
        public Node<T> Head
        {
            get { return this.tHead; }
            set { this.tHead = value; }
        }
        public Linkedlist()
        {
            this.tHead = null;
        }
        public Linkedlist(Node<T> node)
        {
            this.tHead = node;
        }

        public T GetElement(int i)
        {
            throw new NotImplementedException();
        }
        /// <summary>
        /// i最小从1开始
        /// </summary>
        /// <param name="t"></param>
        /// <param name="i"></param>
        public void Insert(T t, int i)
        {
            Node<T> insertNode = new Node<T>(t, null);//实例化添加的node；
            if(this.Head==null||i==1)
            {
                this.Head = insertNode;
            }
            if(i<1|| i>this.GetLength()||(tHead==null&&i==1))
            {
                Console.WriteLine("There are no elements in this linked list!");
                return;  
            }
            int j = 1;
            Node<T> node = tHead;
            Node<T> nodeTmp;
            while(node !=null &&j <i)
            {
                node = node.Next;
                j++;
            }
            nodeTmp = node.Next;
            node.Next = insertNode;
            insertNode.Next = nodeTmp;//待插入的node插入后，其后继node为原来链表的第i+1个node 
        }
        /// <summary>
        /// 添加元素。选择添加位置
        /// </summary>
        /// <param name="t"></param>
        /// <param name="p"></param>
        public void Add(T t, AddPosition p)
        {
            if (p == AddPosition.Tail)
            {
                Add(t);//尾部添加
            }
            else
            {
                Node<T> node = Head;
                Node<T> tmp = new Node<T>(t);
                if (node == null)
                {
                    Head = node;
                }
                else
                {
                    tmp.Next = node;
                    Head = tmp;
                }
            }
        }
        /// <summary>
        /// 添加到尾部
        /// </summary>
        /// <param name="t"></param>
        public void Add(T t)
        {
            Node<T> LastNode=new Node<T>(t,null);
            if(tHead==null)
            {
                tHead = LastNode;
            }
            else
            {
                Node<T> node = tHead;
                while(node.Next!=null)
                {
                    node = node.Next;
                }
                node.Next = LastNode;
            }
        }

        public void Delete(int i)
        {
            if(i<1||i>GetLength())
            {
                Console.WriteLine("Location Error");
                return;
            }
            else
            {
                if (i == 1)
                {
                    Node<T> node = tHead;
                    tHead = node.Next;
                }
                else
                {
                    Node<T> node = tHead;
                    int j = 1;
                    while(j<i)
                    {
                        node = node.Next;
                        j++;
                    }
                    node.Next=node.Next.Next;
                }
            }
        }

        public int GetLength()
        {
            Node<T> node = new Node<T>();
            int count = 0;
            node = Head;
            while (node != null)
            {
                count++;
                node = node.Next;
            }
            return count;
        }
        public T GetElement(int i)
        { 
        if(i<1||i>GetLength())
        {
            Console.WriteLine("Location error");
            return default(T);
        }
        else
        {
            if(i==1)
            {
                return tHead.Data;
            }
            else
            {
                Node<T> node = tHead;
                int j = 1;
                while (j < i)
                {
                    node = node.Next;
                    j++;
                }
                return node.Data;
            }
        }
        }

        public bool IsEmpty()
        {
            return tHead == null;
        }

        public int LocationElement(T t)
        {
            if(tHead==null)
            {
                Console.WriteLine("there is no element in the list");
                return -1;
            }
            Node<T> node = tHead;
            int i = 0;
            while(node!=null)
            {
                i++;
                if (node.Data.Equals(t))
                {
                    return i;
                }
                node = node.Next;
            }
            Console.WriteLine("no found");
            return -1;
        }

        /// <summary>
        /// thead设为null后，则所有后继结点由于失去引用
        /// </summary>
        public void Clear()
        {
            tHead = null;
        }

        public void Reverse()
        {
            if(tHead==null)
            {
                Console.WriteLine("There is no element in the list");
            }
            else
            {
                Node<T> node = tHead;
                if (node.Next == null) { }
                else
                {
                    Node<T> node1 = node.Next;
                    Node<T> node2;
                    while (node != null)
                    {
                        node2 = node.Next.Next;
                        node.Next = node2;//可以发现node始终未变，始终是原来的那个头节点  
                        node1.Next = this.tHead;
                        this.tHead = node1;
                        node1 = node2;
                    }
                }
            }
        }
    }