README.md

Queue using Stack

by Pawan Kumar @jsartisan

Implement a queue data structure using stacks in JavaScript. A queue follows the First-In-First-Out (FIFO) principle. Your queue should have the following methods:

• enqueue(element): Adds an element to the end of the queue.
• dequeue(): Removes the first element from the queue and returns it. Returns undefined if the queue is empty.
• front(): Returns the first element of the queue without removing it. Returns undefined if the queue is empty.
• isEmpty(): Returns true if the queue is empty, otherwise returns false.
• size(): Returns the number of elements in the queue.

Use the following example to understand how the queue should work:

class QueueUsingStacks {
  // Your implementation here
}

const queue = new QueueUsingStacks();
queue.enqueue(1);
queue.enqueue(2);
console.log(queue.front()); // 1
console.log(queue.dequeue()); // 1
console.log(queue.size()); // 1
console.log(queue.isEmpty()); // false
queue.dequeue();
console.log(queue.isEmpty()); // true