C# - Queue Class

It 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.

Methods and Properties of the Queue Class

The following table lists some of the commonly used properties of the Queue class −

Sr.No.	Property & Description
1	Count Gets the number of elements contained in the Queue.

The following table lists some of the commonly used methods of the Queue class −

Sr.No.	Method & Description
1	public virtual void Clear(); Removes all elements from the Queue.
2	public virtual bool Contains(object obj); Determines whether an element is in the Queue.
3	public virtual object Dequeue(); Removes and returns the object at the beginning of the Queue.
4	public virtual void Enqueue(object obj); Adds an object to the end of the Queue.
5	public virtual object[] ToArray(); Copies the Queue to a new array.
6	public virtual void TrimToSize(); Sets the capacity to the actual number of elements in the Queue.

Example

The following example demonstrates use of Stack −

Live Demo

using System;
using System.Collections;

namespace CollectionsApplication {
   class Program {
      static void Main(string[] args) {
         Queue q = new Queue();
         
         q.Enqueue('A');
         q.Enqueue('M');
         q.Enqueue('G');
         q.Enqueue('W');
         
         Console.WriteLine("Current queue: ");
         foreach (char c in q) Console.Write(c + " ");
         
         Console.WriteLine();
         q.Enqueue('V');
         q.Enqueue('H');
         Console.WriteLine("Current queue: ");
         foreach (char c in q) Console.Write(c + " ");
         
         Console.WriteLine();
         Console.WriteLine("Removing some values ");
         char ch = (char)q.Dequeue();
         Console.WriteLine("The removed value: {0}", ch);
         ch = (char)q.Dequeue();
         Console.WriteLine("The removed value: {0}", ch);
         
         Console.ReadKey();
      }
   }
}

When the above code is compiled and executed, it produces the following result −

Current queue: 
A M G W 
Current queue: 
A M G W V H 
Removing values
The removed value: A
The removed value: M

csharp_collections.htm