C# | Getting an enumerator that iterates through LinkedList<T>

LinkedList<T>.GetEnumerator Method is used to get an enumerator that iterates through the LinkedList<T>.

Syntax:

public System.Collections.Generic.LinkedList<T>.Enumerator GetEnumerator ();

Return Value: It returns an LinkedList<T>.Enumerator for the LinkedList<T>.

Below programs illustrate the use of above-discussed method:

Example 1:

// C# code to get an enumerator that
// iterates through the LinkedList<T>
using System;
using System.Collections.Generic;

class GFG {

    // Driver code
    public static void Main()
    {

        // Creating a LinkedList of Integers
        LinkedList<int> myList = new LinkedList<int>();

        // Adding nodes in LinkedList
        myList.AddLast(2);
        myList.AddLast(4);
        myList.AddLast(6);
        myList.AddLast(8);

        // To get an Enumerator
        // for the List.
        LinkedList<int>.Enumerator em = myList.GetEnumerator();
        display(em);
    }

    // display method
    static void display(IEnumerator<int> em)
    {
        while (em.MoveNext()) {
            int val = em.Current;
            Console.WriteLine(val);
        }
    }
}

Output:

2
4
6
8

Example 2:

// C# code to get an enumerator that
// iterates through the LinkedList<T>
using System;
using System.Collections.Generic;

class GFG {

    // Driver code
    public static void Main()
    {

        // Creating a LinkedList of Strings
        LinkedList<String> myList = new LinkedList<String>();

        // Adding nodes in LinkedList
        myList.AddLast("GeeksforGeeks");
        myList.AddLast("GFG");
        myList.AddLast("Data Structures");
        myList.AddLast("Noida");

        // To get an Enumerator
        // for the LinkedList<T>.
        LinkedList<string>.Enumerator em = myList.GetEnumerator();
        display(em);
    }

    // display method
    static void display(IEnumerator<string> em)
    {
        while (em.MoveNext()) {
            string val = em.Current;
            Console.WriteLine(val);
        }
    }
}

Output:

GeeksforGeeks
GFG
Data Structures
Noida

Note:

• The foreach statement of the C# language hides the complexity of the enumerators. Therefore, using foreach is recommended, instead of directly manipulating the enumerator.
• Enumerators can be used to read the data in the collection, but they cannot be used to modify the underlying collection.
• Current returns the same object until either MoveNext or Reset is called. MoveNext sets Current to the next element.
• An enumerator remains valid as long as the collection remains unchanged. If changes are made to the collection, such as adding, modifying, or deleting elements, the enumerator is irrecoverably invalidated and its behavior is undefined.
• This method is an O(1) operation.

Reference:

• https://docs.microsoft.com/en-us/dotnet/api/system.collections.generic.linkedlist-1.getenumerator?view=netframework-4.7.2