package com.sarvesh.javabasics; public class CustomQueue { int[] arr; int front; int rear; public CustomQueue(int size) { arr = new int[size]; front = 0; rear = 0; } public void enqueue(int x) { if (rear == arr.length) { System.out.println("The line is full! Cannot add " + x); return; } arr[rear] = x; rear++; } public int dequeue() { if (front == rear) { System.out.println("The line is empty!"); return -1; } int servedPerson = arr[front]; front++; return servedPerson; } public int peek() { if (front == rear) return -1; return arr[front]; } public static void main(String[] args) { CustomQueue engine = new CustomQueue(5); engine.enqueue(10); engine.enqueue(20); engine.enqueue(30); System.out.println("Served: " + engine.dequeue()); System.out.println("Next up: " + engine.peek()); } }