Insert linked list node at nth last position in kotlin

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

// Kotlin program for
// Insert linked list node at nth last position 

// Linked list node
class LinkNode
{
	var data: Int;
	var next: LinkNode ? ;
	constructor(data: Int)
	{
		this.data = data;
		this.next = null;
	}
}
class LinkedList
{
	var head: LinkNode ? ;
	constructor()
	{
		this.head = null;
	}
	// insert node at end position
	fun insert(value: Int): Unit
	{
		// Create a new node
		val node: LinkNode = LinkNode(value);
		if (this.head == null)
		{
			this.head = node;
		}
		else
		{
			var temp: LinkNode ? = 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
	fun display(): Unit
	{
		if (this.head == null)
		{
			return;
		}
		var temp: LinkNode ? = this.head;
		// iterating linked list elements
		while (temp != null)
		{
			print(""+ temp.data + " → ");
			// Visit to next node
			temp = temp.next;
		}
		println("NULL");
	}
	// Add node at specific position from the end of linked list
	fun endPosition(n: Int, value: Int): Unit
	{
		if (this.head == null)
		{
			println("Empty Linked list");
		}
		else if (n <= 0)
		{
			println("Invalid position");
		}
		else
		{
			var temp: LinkNode ? = this.head;
			var location: LinkNode ? = null;
            var position = n;
			while (temp != null)
			{
				position -= 1;
				if (position <= 0)
				{
					if (location == null)
					{
						location = this.head;
					}
					else
					{
						location = location.next;
					}
				}
				// Visit to next node
				temp = temp.next;
			}
			if (position <= 1)
			{
				val node: LinkNode = 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
			{
				println("Opps position not found");
			}
		}
	}
}
fun main(args: Array < String > ): Unit
{
	val sll: LinkedList = LinkedList();
	// Add node
	sll.insert(5);
	sll.insert(4);
	sll.insert(3);
	sll.insert(2);
	sll.insert(1);
	sll.display();
	val position: Int = 2;
	val data: Int = 10;
	sll.endPosition(position, data);
	println(" 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