Exercise $2$:

Abstract Concept of a Queue:

A queue is a collection of elements where the first added element is the first to be removed. It follows

the FIFO $($First$-$In$-$First$-$Out$)$ principle. For example, imagine a queue at a ticket counter; the person

who enters the queue first gets served first.

Design and Implementation of a Queue Abstract Data Type $($ADT$)$:

Design and implement a queue ADT with the following specifications:

The queue should support generic types to allow for flexibility in the type of elements it can

hold.

Implement methods to enqueue $($add$)$ an element to the rear end of the queue, dequeue $($remove$)$

an element from the front end of the queue, and check if the queue is empty.

Write appropriate documentation for the queue class and methods, including an overview,

abstraction function, rep invariant, and any necessary comments.

Ensure that the queue's internal representation is encapsulated properly.

Implement the repOK $()$ method to check if the rep invariant holds true for the current state of

the queue.

Implement the toString$()$ method to provide a string representation of the queue's elements.

Your task:

Define the abstract concept of a queue based on the provided description.

Design the queue ADT by specifying its methods and behaviours.

Implement the queue ADT in Java, ensuring proper encapsulation and adherence to the defined

specifications.

Implement the provided main function to test the functionality of your queue implementation.

Submit your solution with the main function and ensure your implementation produces the

expected output.

public class Main $\{$

public static void main$($String$[]$ args$)\{$

$//$ Test the queue implementation

Queue queue $=$ new Queue;

$//$ Enqueue elements

queue.enqueue$(10)$;

queue.enqueue$(20)$;

queue.enqueue$(30)$;

$//$ Dequeue elements

int dequeuedElement$1=$ queue.dequeue$()$; $//10$

int dequeuedElement$2=$ queue.dequeue$()$; $//20$

$//$ Check if the queue is empty

boolean isEmpty $=$ queue.isEmpty$()$; $//$ false

$//$ Expected output

System.out.println$("$Dequeued element $1$: $"+$ dequeuedElement$1)$;

System.out.println$("$Dequeued element $2$: $"+$ dequeuedElement$2)$;

System.out.println$("$Is the queue empty? $"+$ isEmpty$)$;

$\}$

$\}$