Queue implementation in java

ghz 10months ago ⋅ 140 views

Sure, here's a basic implementation of a queue in Java using an array:

public class Queue {
    private int maxSize; // Maximum size of the queue
    private int[] queueArray;
    private int front; // Front of the queue
    private int rear; // Rear of the queue
    private int currentSize; // Current size of the queue

    // Constructor to initialize the queue
    public Queue(int size) {
        maxSize = size;
        queueArray = new int[maxSize];
        front = 0;
        rear = -1;
        currentSize = 0;
    }

    // Method to check if the queue is empty
    public boolean isEmpty() {
        return currentSize == 0;
    }

    // Method to check if the queue is full
    public boolean isFull() {
        return currentSize == maxSize;
    }

    // Method to get the current size of the queue
    public int size() {
        return currentSize;
    }

    // Method to insert an element into the queue
    public void enqueue(int item) {
        if (isFull()) {
            System.out.println("Queue is full. Cannot enqueue " + item);
            return;
        }
        rear = (rear + 1) % maxSize;
        queueArray[rear] = item;
        currentSize++;
    }

    // Method to remove an element from the queue
    public int dequeue() {
        if (isEmpty()) {
            System.out.println("Queue is empty. Cannot dequeue.");
            return -1;
        }
        int removedItem = queueArray[front];
        front = (front + 1) % maxSize;
        currentSize--;
        return removedItem;
    }

    // Method to view the front element of the queue
    public int peek() {
        if (isEmpty()) {
            System.out.println("Queue is empty. No element to peek.");
            return -1;
        }
        return queueArray[front];
    }

    public static void main(String[] args) {
        Queue queue = new Queue(5);
        queue.enqueue(1);
        queue.enqueue(2);
        queue.enqueue(3);
        queue.enqueue(4);
        queue.enqueue(5);

        System.out.println("Front element: " + queue.peek());
        System.out.println("Dequeued element: " + queue.dequeue());
        System.out.println("Front element after dequeue: " + queue.peek());
    }
}

This implementation includes methods for checking if the queue is empty or full, getting the current size of the queue, enqueueing elements, dequeueing elements, and peeking at the front element of the queue. It's a basic implementation and doesn't include error handling for all scenarios.

#algorithm