How to find a node with a specified value in linked list in C#

The LinkedList<T> generic class in the System.Collections.Generic namespace provides the Find() method.

We can use this method to find the first node with the specified value in a linked list in C#.

Syntax

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

using System;
using System.Collections.Generic;
class LinkedListFind {
    static void Main() {
        LinkedList<string> monthList = new LinkedList<string>();
        
        monthList.AddLast("January");
        monthList.AddLast("February");
        monthList.AddLast("February");
        monthList.AddLast("April");
        
        Console.WriteLine("LinkedList Elements");
        Print(monthList);
        
        string serachMonth1 = "February", serachMonth2 = "December";
        LinkedListNode<string> result = monthList.Find(serachMonth1);
        
        Console.WriteLine($"Searching list for {serachMonth1}");
        
        if(result!=null) {
         Console.WriteLine($"Found a node with value {result.Value}, previous Node : {result.Previous.Value}");
        } else {
          Console.WriteLine($"No node found with {serachMonth1} value");
        }
        result = monthList.Find(serachMonth2);
        Console.WriteLine($"Searching list for {serachMonth2}");
        
        if(result!=null) {
          Console.WriteLine($"Found a node with value {result.Value}");
        } else {
          Console.WriteLine($"No node found with {serachMonth2} value");
        }
    }
    private static void Print(LinkedList<string> list) { 
        foreach (var node in list) {
            Console.Write(node + ", ");
        }
        Console.WriteLine("\n");        
    }
}

Explanation

After we initialize the linked list, we call the Find() method with the passing February string to find in the list.

The search performs a linear search (i.e., O(1)) in the list and returns the linked list node with the February value, and the previous node is January.

We also print the returned node value and its previous node value in the output.

Next, we call the Find() method by passing the input string as December to search in the list. It performs a linear search in the list and returns null as there is no node in the list with that value.

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