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.Objects stored in a Queue are inserted at one end and removed from the other.
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<T> is the class in the System.Collection.Generic Namespace, where T specifies the type of elements in the queue
Constructors:-
Queue<T> Constructor - Initializes a new instance of the Queue<T> class that is empty. The next lines shows how we create the empty queue.
Queue<string> queue = new Queue<string>();
Queue<T> Constructor (IEnumerable<T>) - Initializes a new instance of the Queue<T> class that contains elements copied from the specified collection.
string[] courses = { "10th","12th", "Bsc","Msc", "M. Phil","M. Pharama" };
Queue<string> queue = new Queue<string>(courses);
Queue<T> Constructor (Int32) - Initializes a new instance of the Queue<T> class that is empty and has the specified initial capacity.
Queue<string> queue = new Queue<string>(4);
Operation on Queue:-
Property of Queue:-
Source code example:-
using System;
using System.Collections;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleAppDemo
{
class Program
{
static void Main(string[] args)
{
stackOperations classObj = new stackOperations();
while (true)
{
// Console.Clear();
Console.WriteLine("\n");
Console.WriteLine("1. Add an element");
Console.WriteLine("2. See the First element.");
Console.WriteLine("3. Remove First element.");
Console.WriteLine("4. Display Queue elements.");
Console.WriteLine("5. Exit");
Console.Write("Select your choice: ");
int choice = Convert.ToInt32(Console.ReadLine());
switch (choice)
{
case 1:
classObj.Enqueue();
break;
case 2: classObj.Peek();
break;
case 3: classObj.Dequeue();
break;
case 4: classObj.Display();
break;
case 5: System.Environment.Exit(1);
break;
}
Console.ReadKey();
}
}
}
class stackOperations
{
string item;
Queue<string> qObj = new Queue<string>();
public bool isEmpty()
{
if (qObj.Count == 0) return true;
return false;
}
public void Enqueue()
{
Console.Write("\nEnter a Item\n");
item = Console.ReadLine();
qObj.Enqueue(item);
Console.WriteLine("\nItem Added successfully!");
}
public void Dequeue()
{
if (isEmpty())
{
Console.WriteLine("Queue is empty!");
}
else
{
qObj.Dequeue();
Console.WriteLine("Removed Successfuly");
}
}
public void Peek()
{
if (isEmpty())
{
Console.WriteLine("Queue is empty!");
}
else
{
Console.Write("First Item is: {0}", qObj.Peek());
}
}
public void Display()
{
if (isEmpty())
{
Console.WriteLine("Queue is empty!");
}
else
{
Console.Write("\nItems in Queue are: \n");
foreach (string item in qObj)
{
Console.Write(item);
Console.Write("\n");
}
}
}
}
}
