Singly LinkedList Traversal using C#

A LinkedList in C# is a doubly-linked list that allows efficient insertion and removal of elements. Traversal refers to visiting each node in the LinkedList sequentially to access or process the data.

The LinkedList<T> class in C# provides various methods to traverse through its elements, with the most common approach being the foreach loop.

Syntax

Following is the syntax for declaring a LinkedList −

var linkedList = new LinkedList<DataType>();

Following is the syntax for traversing a LinkedList using foreach −

foreach(var item in linkedList) {
   // Process each item
}

Using foreach Loop for Traversal

The simplest and most commonly used method to traverse a LinkedList is using a foreach loop, which automatically handles the iteration −

using System;
using System.Collections.Generic;

public class Demo {
   public static void Main(string[] args) {
      var a = new LinkedList<string>();
      a.AddLast("Tim");
      a.AddLast("Tom");
      a.AddLast("John");
      a.AddLast("Alice");

      Console.WriteLine("Traversing LinkedList:");
      foreach(var res in a) {
         Console.WriteLine(res);
      }
   }
}

The output of the above code is −

Traversing LinkedList:
Tim
Tom
John
Alice

Using LinkedListNode for Manual Traversal

You can also traverse a LinkedList manually using LinkedListNode<T> objects, which provides more control over the traversal process −

using System;
using System.Collections.Generic;

public class Demo {
   public static void Main(string[] args) {
      var numbers = new LinkedList<int>();
      numbers.AddLast(10);
      numbers.AddLast(20);
      numbers.AddLast(30);
      numbers.AddLast(40);

      Console.WriteLine("Manual traversal using nodes:");
      LinkedListNode<int> current = numbers.First;
      while(current != null) {
         Console.WriteLine("Value: " + current.Value);
         current = current.Next;
      }
   }
}

The output of the above code is −

Manual traversal using nodes:
Value: 10
Value: 20
Value: 30
Value: 40

Reverse Traversal

Since LinkedList in C# is doubly-linked, you can traverse it in reverse order starting from the last node −

using System;
using System.Collections.Generic;

public class Demo {
   public static void Main(string[] args) {
      var fruits = new LinkedList<string>();
      fruits.AddLast("Apple");
      fruits.AddLast("Banana");
      fruits.AddLast("Orange");
      fruits.AddLast("Mango");

      Console.WriteLine("Forward traversal:");
      foreach(var fruit in fruits) {
         Console.WriteLine(fruit);
      }

      Console.WriteLine("\nReverse traversal:");
      LinkedListNode<string> current = fruits.Last;
      while(current != null) {
         Console.WriteLine(current.Value);
         current = current.Previous;
      }
   }
}

The output of the above code is −

Forward traversal:
Apple
Banana
Orange
Mango

Reverse traversal:
Mango
Orange
Banana
Apple

Conclusion

LinkedList traversal in C# can be accomplished using foreach loops for simple iteration or manually using LinkedListNode<T> objects for more control. The doubly-linked nature allows both forward and reverse traversal efficiently.