javascript-with-sai/classes.html at master · junaid537/javascript-with-sai · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        // program to implement queue data structure

class Queue {
    constructor() {
        this.items = [];
    }

    // add element to the queue
    enqueue(element) {
        return this.items.push(element);
    }

    // remove element from the queue
    dequeue() {
        if(this.items.length > 0) {
            return this.items.shift();
        }
    }

    // view the last element
    rear() {
        return this.items[this.items.length - 1];
    }

    front(){
        return this.items[0];
    }

    // check if the queue is empty
    isEmpty(){
       return this.items.length == 0;
    }


    // empty the queue
    clear(){
        this.items = [];
    }
    // the size of the queue
    size(){
        return this.items.length;
    }
}

let queue = new Queue();
queue.enqueue(10);
queue.enqueue(11);
queue.enqueue(22);
queue.enqueue(44);
queue.enqueue(66);
console.log(queue.items);//[10,11,12,44,66]

queue.dequeue();
console.log(queue.items);//[11,12,44,66]

console.log(queue.rear());//66

console.log(queue.isEmpty());//false

console.log(queue.size());//4

queue.clear();
console.log(queue.items);//[]


/*-------------------instanceof operator-----------------------


The following shows the syntax of the instanceof operator:

object instanceof contructor
In this syntax:

object is the object to test.
constructor is a function to test against.
*/

function Person(name) {
  this.name = name;
}

let p1 = new Person('John');

console.log(p1 instanceof Person); // true

//It returns true because the Person.prototype appears on the prototype chain of the p1 object.
//The prototype chain of the p1 is the link between p1, Person.prototype, and Object.prototype
    </script>
</body>
</html>