Simple Queue Example Java Program


Definition

In a billing counter, the customer or object at the front of the line was the first one to enter, while at the end of the line is the last to have entered. Every time a customer finishes paying for their items (or person steps off the escalator or the machine part is removed from the assembly line, etc.) that object leaves the queue from the front. This represents the queue/dequeue function. Every time another object or customer enters the line to wait, they join the end of the line and represent the ?enqueue? function. The queue.size a function would return the length of the line, and the empty a function would return true only if there was nothing in the line.

Example Program

import java.util.*;

public class QueueExample {

    public static void main(String[] args) {
        Queue<String> locationsQueue = new LinkedList<>();

        locationsQueue.add("Chennai");
        locationsQueue.add("Mumbai");
        locationsQueue.add("Hyderabad");
        locationsQueue.add("Lucknow");
        locationsQueue.add("Bengaluru");

        System.out.println("Queue is : " + locationsQueue);
        System.out.println("Head of Queue : " + locationsQueue.peek());
        locationsQueue.remove();
        System.out.println("After removing Head of Queue : " + locationsQueue);
        System.out.println("Size of Queue : " + locationsQueue.size());
    }
}

Sample Output

Queue is : [Chennai, Mumbai, Hyderabad, Lucknow, Bengaluru]
 Head of Queue : Chennai
 After removing Head of Queue : [Mumbai, Hyderabad, Lucknow, Bengaluru]
 Size of Queue : 4