C# | Add an object to the end of the Queue – Enqueue Operation

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 dequeue.

Queue<T>.Enqueue(T) Method is used to add an object to the end of the Queue<T>.

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 :

void Enqueue(object obj);

The Enqueue() method inserts values at the end of the Queue.

Example:

// C# code to add an object
// to the end of 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("one");

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

        Console.WriteLine(myQueue.Count);

        myQueue.Enqueue("two");

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

        Console.WriteLine(myQueue.Count);

        myQueue.Enqueue("three");

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

        Console.WriteLine(myQueue.Count);

        myQueue.Enqueue("four");

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

        Console.WriteLine(myQueue.Count);

        myQueue.Enqueue("five");

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

        Console.WriteLine(myQueue.Count);

        myQueue.Enqueue("six");

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

        Console.WriteLine(myQueue.Count);
    }
}

Output:

Total number of elements in the Queue are : 1
Total number of elements in the Queue are : 2
Total number of elements in the Queue are : 3
Total number of elements in the Queue are : 4
Total number of elements in the Queue are : 5
Total number of elements in the Queue are : 6

Reference:

• https://docs.microsoft.com/en-us/dotnet/api/system.collections.generic.queue-1.enqueue?view=netframework-4.7.2#System_Collections_Generic_Queue_1_Enqueue__0_