How to add a node to the start of a linked list in C#

The LinkedList<T> generic class in the System.Collections.Generic namespace provides the AddFirst() method, which can be used to add a node at the start of the linked list in C#.

Syntax

public System.Collections.Generic.LinkedListNode<T> AddFirst (T value);

The method takes the value T as input and returns a new LinkedListNode<T> containing the passed input value.
The method has an overload available that takes LinkedListNode<T> as input and adds it to the start of the list.

Things to note

This method is an O(1) operation.
LinkedList<T> accepts null as a valid reference type value.
LinkedList<T> allows duplicate values as well.
For an empty linked list, the new node becomes the First and the Last node.

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

How to add a node to the start of a linked list in C#

Syntax

Things to note

Code

Explanation