C# Queue Tutorial For Beginners With Examples

Queue is a type of collection in which the item stored first is retrieved first. This behaviour is also called as FIFO i.e. First In First Out.

Inserting an item into a Queue is called as Enqueuing and removing an item is called as Dequeuing.

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Important features of C# Queue class

Below are some of the important features of a Queue class.

• Null values can be stored in Queue.
• Duplicate values can be stored in Queue.
• It has both generic and non-generic versions.

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Create a Queue in C#

A Queue can be created by using the below code.

    Queue serviceStation = new Queue();
        

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Add items to a C# Queue

To add items to a Queue the Enqueue method is used.

    serviceStation.Enqueue("A");    
        

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Remove items from a C# Queue

To remove items from a Queue the Dequeue method is used.

Since it follows the FIFO pattern so the items added first to the queue will be removed first.

    
    serviceStation.Dequeue();
        

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Foreach loop to access items in a C# Queue

To access all the items stored in a Queue a foreach loop can be used.

    Queue serviceStation = new Queue();

    serviceStation.Enqueue("A");
    serviceStation.Enqueue("B");
    serviceStation.Enqueue("C");
                        
    foreach (object obj in serviceStation)
    {
        Console.WriteLine("Item: " + obj);
    }
        

Output:
Item: A
Item: B
Item: C

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Methods and Properties of a C# Queue

Commonly used methods of a Queue are:

Method	Description
Clear	Removes all the items from a Queue.
Contains	Determines whether an item is present in a Queue.
Peek	Gets the first item present in the beginning of a Queue without removing it.
Enqueue	Adds an item to the end of a Queue.
Dequeue	Removes the first item present in the beginning of a Queue.

Commonly used properties of a Queue are:

Property	Description
Count	Returns the number of items present in a Queue.