为什么插入函数不起作用

Question

我写了一段代码来实现链表并在某个位置添加一个新节点。

public class Node
{
    //this is the class which creates each node.
    public Node NextInstance; //this is the instance which creates the node.
    public object data; // this will have the data
    public Node(object data) //Constructer
    {
        this.data = data;
    }
    public Node()
    {
    }
}
public class LinkedList
{
    Node Head; // this is for the head instance.
    Node Current;
    Node temp1;
    // Add the method which will create a node
    public void Add_Node(Node N)
    {
        if (Head == null)
        {
            //if the head is null, set the first instance to head
            Head = N; // "First" = Head
            Current = Head; // Set the Current to Head; Current = "First"
        }
        else
        {
            Current.NextInstance = N; // Current.NextInstance = "Second";
            Current = Current.NextInstance; //Current = "Second";
        }
    }
    public void Print_Nodes()
    { 
        //this is the method to print the instance
        temp1 = Head;
        while (Head != null)
        {
            //just traverse 
            Console.WriteLine(Head.data);
            Head = Head.NextInstance;
        }
    }
    public void Insert_Node(int position, string Val)
    {
        Node T = new Node(Val);
        Node temp;
        //T.data = Val;
        int k = 0;
        Head = temp1;
        while (Head != null)
        {
            k += 1;
            if (k == position)
            {
                temp = Head;
                Head = T;
                Head.NextInstance = temp;
            }
            Head = Head.NextInstance;
        }
    }
}
class Program
{
    static void Main(string[] args)
    {
        LinkedList LL = new LinkedList();
        LL.Add_Node(new Node("First"));
        LL.Add_Node(new Node("Second"));
        LL.Add_Node(new Node("Third"));
        //LL.Print_Nodes();
        LL.Insert_Node(2, "Shef");
        LL.Print_Nodes();
        Console.ReadLine();
    }
}

Insert_Node中的代码工作不正常。有人能纠正我吗？

Answer 1

如果新节点不是head，则不应该更改head节点。

        public void Insert_Node(int position, string Val)
    {
        Node T = new Node(Val);
        Node temp = Head;
        int i = 0;
        if (position == i)
        {
            T.NextInstance = Head;
            Head = T;
        }
        else
        {
            while (temp != null && i < position-1)
            {
                temp = temp.NextInstance;
                i++;
            }
            T.NextInstance = temp.NextInstance;
            temp.NextInstance = T;
        }
    }