Queue.Contains() Method in C#

This method is used to check whether an element is in the Queue. This method performs a linear search, therefore, this method is an O(n) operation, where n is Count. And this method comes under the System.Collections namespace.

Syntax:

public virtual bool Contains(object obj);

Here, obj is the Object to locate in the Queue. The value can be null.

Return Value: The function returns True if the element exists in the Queue and returns False if the element doesn’t exist in the Queue.

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

Example 1:

C#

// C# code to illustrate the
// Queue.Contains() Method
using System;
using System.Collections;

class GFG {

    // Driver code
    public static void Main()
    {

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

        // Inserting the elements into the Queue
        myQueue.Enqueue(5);
        myQueue.Enqueue(10);
        myQueue.Enqueue(15);
        myQueue.Enqueue(20);
        myQueue.Enqueue(25);

        // Checking whether the element is
        // present in the Queue or not
        // The function returns True if the
        // element is present in the Queue, else
        // returns False
        Console.WriteLine(myQueue.Contains(7));
    }
}

Output:

False

Example 2:

C#

// C# code to illustrate the
// Queue.Contains() Method
using System;
using System.Collections;

class GFG {

    // Driver code
    public static void Main()
    {

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

        // Inserting the elements into the Queue
        myQueue.Enqueue("Geeks");
        myQueue.Enqueue("Geeks Classes");
        myQueue.Enqueue("Noida");
        myQueue.Enqueue("Data Structures");
        myQueue.Enqueue("GeeksforGeeks");

        // Checking whether the element is
        // present in the Queue or not
        // The function returns True if the
        // element is present in the Queue, else
        // returns False
        Console.WriteLine(myQueue.Contains("GeeksforGeeks"));
    }
}

Output:

True

Reference:

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