// A class to represent a queue class QueueImplementation { private int[] arr; // array to store queue elements private int front; // front points to the front element in the queue private int rear; // rear points to the last element in the queue private int capacity; // maximum capacity of the queue private int count; // current size of the queue // Constructor to initialize a queue QueueImplementation(int size) { arr = new int[size]; capacity = size; front = 0; rear = -1; count = 0; } // Utility function to dequeue the front element public void dequeue() { // check for queue underflow if (isEmpty()) { System.out.println("Underflow\nProgram Terminated"); System.exit(1); } System.out.println("Removing " + arr[front]); front = (front + 1) % capacity; count--; } // Utility function to add an item to the queue public void enqueue(int item) { // check for queue overflow if (isFull()) { System.out.println("Overflow\nProgram Terminated"); System.exit(1); } System.out.println("Inserting " + item); rear = (rear + 1) % capacity; arr[rear] = item; count++; } // Utility function to return the front element of the queue public int peek() { if (isEmpty()) { System.out.println("Underflow\nProgram Terminated"); System.exit(1); } return arr[front]; } // Utility function to return the size of the queue public int size() { return count; } // Utility function to check if the queue is empty or not public Boolean isEmpty() { return (size() == 0); } // Utility function to check if the queue is full or not public Boolean isFull() { return (size() == capacity); } } class Queue { public static void main(String[] args) { // create a queue of capacity 5 QueueImplementation q = new QueueImplementation(5); q.enqueue(1); q.enqueue(2); q.enqueue(3); System.out.println("The front element is " + q.peek()); q.dequeue(); System.out.println("The front element is " + q.peek()); System.out.println("The queue size is " + q.size()); q.dequeue(); q.dequeue(); if (q.isEmpty()) { System.out.println("The queue is empty"); } else { System.out.println("The queue is not empty"); } } }