Implementation of queue using queue class

Another way of using queues in python is via the queue class available in Queue module. It has numerous functions and is widely used along with threads for multi-threading operations. It further has FIFO, LIFO, and priority types of queues. However, we'll implement a simple queue using the queue class of the python library.

The queue class is imported from the Queue module. The queue is initialized using the Queue() constructor. Note that it accepts a maxsize() argument, specifying an upper boundary of queue size to throttle memory usage.

We use the put() function to add elements to the queue, and the get() function to remove elements from the queue. Since we have a maxsize check here, we have two other functions to check empty and full conditions. The function empty() returns a boolean true if the queue is empty and false if otherwise. Likewise, the full() function returns a boolean true if the queue is full and false if otherwise.

Here, we added elements to the queue and checked for the full condition using q.full(). Since the maxsize is four and we added four elements, the boolean is set to true.

Later, we removed three elements, leaving one element in the queue. Hence the q.empty() function returned boolean false.

You can find more functions on deque collections here.

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// JavaScript program to demonstrate the implementation of a queue using an array

​

let q = [];

​

// Initializing a queue with maxsize 4

let maxSize = 4;

​

// Enqueue elements to queue

q.push('a');

q.push('b');

q.push('c');

q.push('d');

​

// Return Boolean for Full Queue

console.log("\nFull:", q.length === maxSize);

​

// Dequeue elements from queue

console.log("\nElements dequeued from the queue");

console.log(q.shift());

console.log(q.shift());

console.log(q.shift());

​

// Return Boolean for Empty Queue

console.log("\nEmpty:", q.length === 0);

​

// Print the size of the queue

console.log("\nQueue size:", q.length);