Get the last node of the LinkedList in C#

In C#, you can get the last node of a LinkedList<T> using the Last property. This property returns a LinkedListNode<T> object representing the last node in the list, or null if the list is empty.

Syntax

Following is the syntax to get the last node of a LinkedList −

LinkedListNode<T> lastNode = linkedList.Last;
T lastValue = linkedList.Last.Value;

Using Last Property with String LinkedList

The following example demonstrates how to access the last node in a string LinkedList −

using System;
using System.Collections.Generic;

public class Demo {
   public static void Main() {
      LinkedList<string> list = new LinkedList<string>();
      list.AddLast("A");
      list.AddLast("B");
      list.AddLast("C");
      list.AddLast("D");
      list.AddLast("E");
      list.AddLast("F");
      list.AddLast("G");
      list.AddLast("H");
      list.AddLast("I");
      list.AddLast("J");
      
      Console.WriteLine("Count of nodes = " + list.Count);
      Console.WriteLine("First Node = " + list.First.Value);
      Console.WriteLine("Last Node = " + list.Last.Value);
      
      list.Clear();
      Console.WriteLine("Count of nodes (updated) = " + list.Count);
   }
}

The output of the above code is −

Count of nodes = 10
First Node = A
Last Node = J
Count of nodes (updated) = 0

Using Last Property with Integer LinkedList

Here's another example using an integer LinkedList −

using System;
using System.Collections.Generic;

public class Demo {
   public static void Main() {
      LinkedList<int> list = new LinkedList<int>();
      list.AddLast(100);
      list.AddLast(200);
      list.AddLast(300);
      list.AddLast(400);
      list.AddLast(500);
      list.AddLast(600);
      list.AddLast(700);
      list.AddLast(800);
      list.AddLast(900);
      list.AddLast(1000);
      
      Console.WriteLine("Count of nodes = " + list.Count);
      Console.WriteLine("First Node = " + list.First.Value);
      Console.WriteLine("Last Node = " + list.Last.Value);
      
      list.Clear();
      Console.WriteLine("Count of nodes (updated) = " + list.Count);
   }
}

The output of the above code is −

Count of nodes = 10
First Node = 100
Last Node = 1000
Count of nodes (updated) = 0

Handling Empty LinkedList

When working with the Last property, it's important to check if the LinkedList is empty to avoid null reference exceptions −

using System;
using System.Collections.Generic;

public class Demo {
   public static void Main() {
      LinkedList<string> list = new LinkedList<string>();
      
      // Check if list is empty before accessing Last
      if (list.Last != null) {
         Console.WriteLine("Last Node = " + list.Last.Value);
      } else {
         Console.WriteLine("LinkedList is empty");
      }
      
      // Add some elements
      list.AddLast("First");
      list.AddLast("Second");
      list.AddLast("Third");
      
      // Now safe to access Last
      Console.WriteLine("Last Node = " + list.Last.Value);
   }
}

The output of the above code is −

LinkedList is empty
Last Node = Third

Key Points

• The Last property has O(1) time complexity as LinkedList maintains references to both first and last nodes.

• Last returns null if the LinkedList is empty.

• Use Last.Value to get the actual data stored in the last node.

• Always check for null before accessing Last.Value to avoid exceptions.

Conclusion

The Last property provides an efficient way to access the last node of a LinkedList in C#. Always verify that the LinkedList is not empty before accessing the Value property to prevent null reference exceptions.