Queue.Clone() Method in C#

This method is used to create a shallow copy of the Queue. It just creates a copy of the Queue. The copy will have a reference to a clone of the internal elements but not a reference to the original elements.

Syntax: public virtual object Clone ();

Return Value: The method returns an Object which is just the shallow copy of the Queue.

Example 1: Let’s see an example without using a Clone() method and directly copying a Queue using assignment operator ‘=’. In the below code, we can see even if we Dequeue() elements from myQueue2, contents of myQueue is also changed. This is because ‘=’ just assigns the reference of myQueue to myQueue2 and does not create any new Queue. But Clone() creates a new Queue.

// C# program to Copy a Queue using
// the assignment operator
using System;
using System.Collections;

class GFG {

    // Main Method
    public static void Main(string[] args)
    {

        Queue myQueue = new Queue();
        myQueue.Enqueue("Geeks");
        myQueue.Enqueue("Class");
        myQueue.Enqueue("Noida");
        myQueue.Enqueue("UP");

        // Creating a copy using the
        // assignment operator.
        Queue myQueue2 = myQueue;

        myQueue2.Dequeue();

        PrintValues(myQueue);
    }

    public static void PrintValues(IEnumerable myCollection)
    {
        // This method prints all the
        // elements in the Stack.
        foreach(Object obj in myCollection)
            Console.WriteLine(obj);
    }
}

Output:

Class
Noida
UP

Example 2: Here myQueue is unchanged.

// C# program to illustrate the use
// of Object.Clone() Method
using System;
using System.Collections;

class GFG {

    // Main Method
    public static void Main(string[] args)
    {

        Queue myQueue = new Queue();
        myQueue.Enqueue("Geeks");
        myQueue.Enqueue("Class");
        myQueue.Enqueue("Noida");
        myQueue.Enqueue("UP");

        // Creating copy using Clone() method.
        Queue myQueue2 = (Queue)myQueue.Clone();
        myQueue2.Dequeue();

        PrintValues(myQueue);
    }

    public static void PrintValues(IEnumerable myCollection)
    {
        // This method prints all the
        // elements in the Stack.
        foreach(Object obj in myCollection)
            Console.WriteLine(obj);
        Console.WriteLine();
    }
}

Output:

Geeks
Class
Noida
UP

Reference:

• https://docs.microsoft.com/en-us/dotnet/api/system.collections.queue.clone?view=netframework-4.7.2