Insert node at beginning of linked list in c#

Write a program which is create and add new node at the beginning of linked list in csharp.

Here given of code implementation process.

// Include namespace system
using System;
/*
    Csharp program for
    Insert node at beginning of linked list
*/
// Linked list node
public class LinkNode
{
    public int data;
    public LinkNode next;
    public LinkNode(int data)
    {
        this.data = data;
        this.next = null;
    }
}
public class SingleLL
{
    public LinkNode head;
    public SingleLL()
    {
        this.head = null;
    }
    // Adding new node at beginning of linked list
    public void addNode(int data)
    {
        // Create new node
        LinkNode node = new LinkNode(data);
        // Connect current node to previous head
        node.next = this.head;
        this.head = node;
    }
    // Display linked list element
    public void display()
    {
        if (this.head == null)
        {
            return;
        }
        LinkNode temp = this.head;
        // iterating linked list elements
        while (temp != null)
        {
            Console.Write(temp.data + " → ");
            // Visit to next node
            temp = temp.next;
        }
        Console.Write(" NULL\n");
    }
    public static void Main(String[] args)
    {
        SingleLL sll = new SingleLL();
        // Linked list
        // 1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → NULL
        sll.addNode(8);
        sll.addNode(7);
        sll.addNode(6);
        sll.addNode(5);
        sll.addNode(4);
        sll.addNode(3);
        sll.addNode(2);
        sll.addNode(1);
        sll.display();
    }
}

 1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → NULL

Time complexity of above program is O(1).