C# | Remove all objects from the Queue

Queue represents a first-in, first out collection of object. It is used when you need a first-in, first-out access of items. When you add an item in the list, it is called enqueue, and when you remove an item, it is called deque. Queue. Clear Method is used to remove the objects from the Queue. This method is an O(n) operation, where n is total count of elements.

Properties:

• Enqueue adds an element to the end of the Queue.
• Dequeue removes the oldest element from the start of the Queue.
• Peek returns the oldest element that is at the start of the Queue but does not remove it from the Queue.
• The capacity of a Queue is the number of elements the Queue can hold.
• As elements are added to a Queue, the capacity is automatically increased as required by reallocating the internal array.
• Queue accepts null as a valid value for reference types and allows duplicate elements.

Syntax :

public virtual void Clear();

Below given are some examples to understand the implementation in a better way:

Example 1:

// C# code to Remove all
// objects from the Queue
using System;
using System.Collections.Generic;

class GFG {

    // Driver code
    public static void Main()
    {

        // Creating a Queue of strings
        Queue<string> myQueue = new Queue<string>();

        // Inserting the elements into the Queue
        myQueue.Enqueue("1st Element");
        myQueue.Enqueue("2nd Element");
        myQueue.Enqueue("3rd Element");
        myQueue.Enqueue("4th Element");
        myQueue.Enqueue("5th Element");
        myQueue.Enqueue("6th Element");

        // Displaying the count of elements
        // contained in the Queue before
        // removing all the elements
        Console.Write("Total number of elements in the Queue are : ");

        Console.WriteLine(myQueue.Count);

        // Removing all elements from Queue
        myQueue.Clear();

        // Displaying the count of elements
        // contained in the Queue after
        // removing all the elements
        Console.Write("Total number of elements in the Queue are : ");

        Console.WriteLine(myQueue.Count);
    }
}

Output:

Total number of elements in the Queue are : 6
Total number of elements in the Queue are : 0

Example 2:

// C# code to Remove all
// objects from the Queue
using System;
using System.Collections.Generic;

class GFG {

    // Driver code
    public static void Main()
    {

        // Creating a Queue of Integers
        Queue<int> myQueue = new Queue<int>();

        // Inserting the elements into the Queue
        myQueue.Enqueue(3);
        myQueue.Enqueue(5);
        myQueue.Enqueue(7);
        myQueue.Enqueue(9);
        myQueue.Enqueue(11);

        // Displaying the count of elements
        // contained in the Queue before
        // removing all the elements
        Console.Write("Total number of elements in the Queue are : ");

        Console.WriteLine(myQueue.Count);

        // Removing all elements from Queue
        myQueue.Clear();

        // Displaying the count of elements
        // contained in the Queue after
        // removing all the elements
        Console.Write("Total number of elements in the Queue are : ");

        Console.WriteLine(myQueue.Count);
    }
}

Output:

Total number of elements in the Queue are : 5
Total number of elements in the Queue are : 0

Reference:

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