How to remove the last node of a linked list in C#

The LinkedList<T> generic class in the System.Collections.Generic namespace provides the RemoveLast() method, which can remove the last node or the node at the end of the linked list.

Syntax

public void RemoveLast ();

Things to note

  • This method is an O(1) operation.

  • It throws an InvalidOperationException if the LinkedList<T> does not have any nodes.

Removing the last node of the list using RemoveLast() method

Code

In the example below, we have created a linked list monthList of strings and added the names of the first few months to it.

using System;
using System.Collections.Generic;
class LinkedListRemover
{
    static void Main()
    {
        LinkedList<string> monthList = new LinkedList<string>();
        monthList.AddLast("January");
        monthList.AddLast("February");
        monthList.AddLast("March");
        monthList.AddLast("April");
        monthList.AddLast("May");
        monthList.AddLast("June");
        Console.WriteLine("LinkedList Elements");
        Print(monthList);
        monthList.RemoveLast();
        Console.WriteLine("LinkedList Elements After RemoveLast()");
        Print(monthList);
        monthList.RemoveLast();
        Console.WriteLine("LinkedList Elements After RemoveLast()");
        Print(monthList);
    }
    private static void Print(LinkedList<string> list)
    { 
        foreach (var node in list)
        {
            Console.Write(node + ", ");
        }
        Console.WriteLine("\n");        
    }
}

Explanation

The linked list contains six strings: " January, February, March, April, May, and June".

We created a helper method, Print(), to display the linked list nodes.

The RemoveLast() method on this linked list removes the node from the end of the list. We can see that the last node, June, is released in the output.

We call the RemoveLast() method again and print the list’s nodes. We can observe that the last element, May, is also removed from the list and is not present in the output.

Please note that the LinkedList<T> class is maintained internally as a doubly-linked list, and RemoveLast() is an O(1) operation.

The program prints the output and exits.

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