Question

This is for Javascript programming language:

A. Class and Constructor Creation Book Class Create a constructor function or ES6 class for a Book object.

The Book object should store the following data in attributes: title and author. Library Class Create a constructor function or ES6 class for a Library object that will be used with the Book class. The Library object should be able to internally keep an array of Book objects.

B. Methods to add Library Class

The class should have the following methods:

o A function named simulate. In this function create a while loop that runs 30 times to simulate 30 days. Each day, iterate over all the books and checkout the book if it is not checked out, check it in if it is. Book Class

o A method named is CheckedOut that returns true if the book is checked out and false if not. o A method named CheckOut that displays “Checking Out … ” Be sure to replace with the actual title of the book.

o A method named CheckIn that displays “Checking In …” Be sure to replace with the actual title of the book.

C. Test Program After you have created the classes.

Create three Book objects and store the following data in them:

Title

Author

Item #1 Code Complete Steve McConnell

Item #2 The Art of Unit Testing Roy Osherove

Item #3 Domain Driven Design Eric Evans Store all three Book objects in an array named “catalog” in the Library class.

Next, create a Library object.

Now, call the simulate function on the library object you just created.

Answer 1

// Class Book to store title and author

class Book{

//constructor to accept title and author

constructor(_title, _author){

this.title = _title;

this.author = _author;

}

}

//Class library to store array of books

class Library{

//constructor that takes an array of books

constructor(_books){

this.catalog = _books;

//create an array to store the status of each book

//assign an initial value false to all the books

//checked out --> True, Checked in --> False

this.status = new Array(_books.length).fill(false);

}

//method simulate to simulate checkin and checkout

simulate(){

//use while loop for 30 days

let days = 30;

while(days > 0){

//for each book in the library

for (let i = 0; i < this.catalog.length; i++){

//check if the booked is checked out?

if(this.CheckedOut(i)){

//check in the book

this.CheckIn(i);

}

else{

//check out the book

this.CheckOut(i);

}

}

//decrement the days

days--;

}

}

//Method CheckedOut, accepts index of the book

CheckedOut(index){

//return the status

return this.status[index];

}

//Method CheckOut

CheckOut(index){

//get the book title

let title = this.catalog[index].title;

//get the book author

let author = this.catalog[index].author;

//display the output

console.log(`Checking Out: \n-------------\nTitle : ${title}\nAuthor: ${author}\n`);

//change the status

this.status[index] = true;

}

//Method CheckIn

CheckIn(index){

//get the book title

let title = this.catalog[index].title;

//get the book author

let author = this.catalog[index].author;

//display the output

console.log(`Checking In: \n-------------\nTitle : ${title}\nAuthor: ${author}\n`);

//change the status

this.status[index] = false;

}

}

//Main Function for Driving the Simulation

let main = ()=>{

//Create 3 books

let books = [];

books.push(new Book("Code Complete", "Steve McConnell"));

books.push(new Book("The Art of Unit Testing" ,"Roy Osherove"));

books.push(new Book("Domain Driven Design","Eric Evans"));

//Create a library object

let library = new Library(books);

//Simulate

library.simulate();

};

//Call the driver function

main();

OUTPUT