Insert linked list node at nth last position in c#

Csharp program for Insert linked list node at nth last position.Here problem description and explanation.

// Include namespace system
using System;
// Csharp program for
// Insert linked list node at nth last position 

// Linked list node
public class LinkNode
{
	public int data;
	public LinkNode next;
	public LinkNode(int data)
	{
		this.data = data;
		this.next = null;
	}
}
public class LinkedList
{
	public LinkNode head;
	public LinkedList()
	{
		this.head = null;
	}
	// insert node at end position
	public void insert(int value)
	{
		// Create a new node
		var node = new LinkNode(value);
		if (this.head == null)
		{
			this.head = node;
		}
		else
		{
			var temp = this.head;
			// Find the last node
			while (temp.next != null)
			{
				// Visit to next node
				temp = temp.next;
			}
			// Add node
			temp.next = node;
		}
	}
	// Display linked list element
	public void display()
	{
		if (this.head == null)
		{
			return;
		}
		var temp = this.head;
		// iterating linked list elements
		while (temp != null)
		{
			Console.Write(temp.data + " → ");
			// Visit to next node
			temp = temp.next;
		}
		Console.WriteLine("NULL");
	}
	// Add node at specific position from the end of linked list
	public void endPosition(int position, int value)
	{
		if (this.head == null)
		{
			Console.WriteLine("Empty Linked list");
		}
		else if (position <= 0)
		{
			Console.WriteLine("Invalid position");
		}
		else
		{
			var temp = this.head;
			LinkNode location = null;
			while (temp != null)
			{
				position--;
				if (position <= 0)
				{
					if (location == null)
					{
						location = this.head;
					}
					else
					{
						location = location.next;
					}
				}
				// visit to next node
				temp = temp.next;
			}
			if (position <= 1)
			{
				var node = new LinkNode(value);
				if (location == null)
				{
					// Add node at first place
					node.next = this.head;
					this.head = node;
				}
				else
				{
					// Add node at intermediate position
					node.next = location.next;
					location.next = node;
				}
			}
			else
			{
				Console.WriteLine("Opps position not found");
			}
		}
	}
	public static void Main(String[] args)
	{
		var sll = new LinkedList();
		// Add node
		sll.insert(5);
		sll.insert(4);
		sll.insert(3);
		sll.insert(2);
		sll.insert(1);
		sll.display();
		var position = 2;
		var data = 10;
		sll.endPosition(position, data);
		Console.WriteLine(" Add " + data + 
                          " at last " + position + "-nd position");
		sll.display();
	}
}

Output

5 → 4 → 3 → 2 → 1 → NULL
 Add 10 at last 2-nd position
5 → 4 → 3 → 2 → 10 → 1 → NULL