The Queue works like FIFO system , a first-in, first-out collection of Objects. Objects stored in a Queue are inserted at one end and removed from the other. The Queue provide additional insertion, extraction, and inspection operations. We can Enqueue (add) items in Queue and we can Dequeue (remove from Queue ) or we can Peek (that is we will get the reference of first item ) item from Queue. Queue accepts null reference as a valid value and allows duplicate elements.
Some important functions in the Queue Class are follows :
Enqueue : Add an Item in Queue
Dequeue : Remove the oldest item from Queue
Peek : Get the reference of the oldest item
Enqueue : Add an Item in Queue
Syntax : Queue.Enqueue(Object)
Object : The item to add in Queue
days.Enqueue("Sunday");
Dequeue : Remove the oldest item from Queue (we don't get the item later)
Syntax : Object Queue.Dequeue()
Returns : Remove the oldest item and return.
days.Dequeue();
Peek : Get the reference of the oldest item (it is not removed permanently)
Syntax : Object Queue.Peek()
returns : Get the reference of the oldest item in the Queue
days.peek();
The following CSharp Source code shows some of commonly used functions :
using System;
using System.Collections;
using System.Windows.Forms;
namespace WindowsApplication1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
Queue days = new Queue();
days.Enqueue("Sunday");
days.Enqueue("Monday");
days.Enqueue("Tuesday");
days.Enqueue("Wednsday");
days.Enqueue("Thursday");
days.Enqueue("Friday");
days.Enqueue("Saturday");
MessageBox.Show (days.Dequeue().ToString ());
if (days.Contains("Monday"))
{
MessageBox.Show("The queue contains Monday");
}
else
{
MessageBox.Show("Does not match any entries");
}
}
}
}
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When you execute the above C# source code , you will get Sunday in the messagebox and then it check the Monday is exist in the queue or not.