Question & Answer: 6 Tweny Thousand Leagues Under the Sea…..

Given below is the code for the question along with output.

Note:

In the sample program run shown in the question, the output is slightly wrong. The quantity and count for each book have been swapped. Probably the order in which it was read from the file is wrong. For example, the inventory.txt shows 20.99 as price and 10 as quantity for the title “Tweny Thousand Leagues Under the Sea”. But the sample run in question shows count = 20 and price =10 (interchanged). Same is the case for all the books. See the output when menu choice 1 is selected to list all books. So the when a book is added into a cart, this wrong price is being considered to calculate total price as well. So the price , count and total price are not correct according to input file.

The program given by me below reads the quantity and price in correct order and hence output is correct. So please don’t compare numeric values from the answer program to that in the sample given in question. Hope I am clear.

When entering title for book, the case is exactly same i.e. its case sensitive.

Please don’t forget to rate the answer if it helped. Thank you.

book.h

#ifndef book_h
#define book_h
class Book
{
private:

char *title;
char *author;
int quantity;
double price;

public:
Book();
~Book();
void display();
const char* getTitle();
const char* getAuthor() ;
int getQuantity();
double getPrice();
void setTitle(char* title);
void setAuthor(char* author);
void setQuantity(int qty);
void setPrice(double price);
};

#endif /* book_h */

book.cpp

#include “book.h”
#include <cstring>
#include <iostream>
using namespace std;
Book::Book()
{
title = NULL;
author = NULL;
quantity = 0;
price = 0;
}
void Book::display()
{
cout << “Title: ” << title << endl;
cout << “Author: ” << author << endl;
cout << “Count: ” << quantity << endl;
cout << “Price: ” << price << endl;
cout << “———————————” << endl;
}

const char* Book::getTitle()
{
return title;
}
const char* Book::getAuthor()
{
return author;
}
int Book::getQuantity()
{
return quantity;
}
double Book::getPrice()
{
return price;
}

void Book::setTitle(char* title)
{
if(this->title != NULL) delete this->title;
this->title = new char[strlen(title) + 1];
strcpy(this->title, title);
}
void Book::setAuthor(char* author)
{
if(this->author != NULL)
delete this->author;
this->author = new char[strlen(author) + 1];
strcpy(this->author, author);
}
void Book::setQuantity(int qty)
{
this->quantity = qty;
}
void Book::setPrice(double price)
{
this->price = price;
}

Book::~Book()
{
if(title != NULL) delete title;
if(author != NULL) delete author;
}

inventory.h

#ifndef inventory_h
#define inventory_h
#include “book.h”

class Inventory
{
private:
Book **books;
int numBooks;
Book *cartBooks[50]; //array of pointers to books
int cartQuantity[50];
int numCartItems;
int totalQuantity;
double totalPrice;
double discount;
void calculateDiscount();
void loadFromFile(char *fname);
int findBook(char *title);
int searchCart(char *title);
public:
Inventory(char* filename);
~Inventory();
int getNumCopies(char *title);
void listBooks();
void listShoppingCart();
bool addBookToCart(char *title, int qty );
bool removeBookFromCart(char *title);
void showTotalPrice();
bool isBookInCart(char *title);
void checkOut();
};

#endif /* inventory_h */

inventory.cpp

#include “inventory.h”
#include <fstream>
#include <iostream>
#include <cstring>
using namespace std;
Inventory::Inventory(char *filename)
{
totalQuantity = 0;
totalPrice = 0;
numBooks = 0;
numCartItems = 0;
loadFromFile(filename);
}
void Inventory::loadFromFile(char *fname)
{
ifstream infile(fname);
char line[100];
double price;
int qty;
if(!infile.is_open())
{
cout << “Input file ” << fname << ” could not be opened ” << endl;
return;
}

infile >> numBooks;

books = new Book*[numBooks];
for(int i = 0; i < numBooks; i++)
{
infile.ignore(); //remove newline
infile.getline(line, 100);
books[i] = new Book;
books[i]->setTitle(line);

infile.getline(line, 100);
books[i]->setAuthor(line);
infile >> price;
books[i]->setPrice(price);
infile >> qty;
books[i]->setQuantity(qty);
}
infile.close();
}
Inventory::~Inventory()
{
for(int i = 0; i < numBooks;i++)
delete books[i];
delete []books;
}
int Inventory::getNumCopies(char *title)
{
int idx = findBook(title);
if(idx == -1)
return 0;
else
return books[idx]->getQuantity();
}

void Inventory::listBooks()
{
for(int i = 0; i < numBooks; i++)
{
books[i]->display();
}
}
void Inventory::listShoppingCart()
{
cout << “— Shopping Cart —” << endl;
if(numCartItems == 0)
{
cout << “**Your Shopping Cart is Empty **” << endl;
return;
}

for(int i = 0; i < numCartItems; i++)
{
cout << “=>Item: ” << cartBooks[i]->getTitle() << endl;
cout << “Price per book: ” << cartBooks[i]->getPrice() << endl;
cout << “Quantity: ” << cartQuantity[i] << endl;
cout << “—————————————-” << endl;
}
cout << endl;
showTotalPrice();
}
int Inventory::findBook(char *title)
{
for(int i = 0; i < numBooks; i++)
{
if(strcmp(books[i]->getTitle(),title) == 0)
return i;
}
return -1;
}
bool Inventory::addBookToCart(char *title, int qty )
{

int cidx = searchCart(title);
if(cidx == -1)
{
int idx = findBook(title);
if(idx == 0 || books[idx]->getQuantity() < qty)
return false;
cidx = numCartItems;
cartBooks[numCartItems] = books[idx];
cartQuantity[numCartItems] = qty;
numCartItems++;
}
else
{
cartQuantity[cidx] += qty;
}
totalQuantity += qty;
totalPrice += qty * cartBooks[cidx]->getPrice();
cartBooks[cidx]->setQuantity( cartBooks[cidx]->getQuantity() – qty);
calculateDiscount();
return true;
}
bool Inventory::removeBookFromCart(char *title)
{
int idx = searchCart(title);
if(idx == -1)
return false;
else
{
//add back to inventory
cartBooks[idx]->setQuantity(cartBooks[idx]->getQuantity() + cartQuantity[idx]);
totalPrice -= cartQuantity[idx] * cartBooks[idx]->getPrice();
totalQuantity -= cartQuantity[idx];
//move other 1 position up
for(int i = idx; i < numCartItems – 1; i++ )
cartBooks[i] = cartBooks[i+1];
numCartItems –;
return true;
}
}
void Inventory::showTotalPrice()
{
cout << “Total before discount: $” << totalPrice << endl;
cout << “Discount is: ” << discount << endl;
cout << “Total: $” << ((1-discount) * totalPrice) << endl;
cout << endl;
}
void Inventory::calculateDiscount()
{
int n = totalQuantity / 5;
discount = 5 * n / 100.0;
}
int Inventory::searchCart(char *title)
{
for(int i = 0 ; i < numCartItems; i++)
if(strcmp(cartBooks[i]->getTitle(), title) == 0)
return i;
return -1;
}
bool Inventory::isBookInCart(char *title)
{
return searchCart(title) != -1;
}
void Inventory::checkOut()
{
cout << “*** CHECKOUT *** ” << endl;
double finalTotal = totalPrice * ( 1 – discount);
cout << “Final Total is: $” << finalTotal << endl;
cout << “Final discount is: ” << discount << endl;
cout << “You saved: $” << (totalPrice – finalTotal) << endl;
cout << “**** THANK YOU FOR SHOPPING WITH US ****” << endl;
}

main.cpp

#include “inventory.h”
#include <iostream>
#include <iomanip>
using namespace std;
void addBook(Inventory &inventory);
void removeBook(Inventory &inventory);

int main()
{
int choice = 0;
char filename[100] = “/Users/raji/Documents/Chegg/c++/Test/Test/bookstore/inventory.txt”;
Inventory inventory(filename);
cout << fixed << setprecision(2);

cout << “############## WELCOME TO OUR BOOKSTORE ##############” << endl << endl;

while(choice != 5)
{
cout << “——– Menu ——–” << endl;
cout << “1. List books to buy.” << endl;
cout << “2. List Shopping cart.” << endl;
cout << “3. Add book to cart.” << endl;
cout << “4. Remove book from cart.” << endl;
cout << “5. Checkout and quit.” << endl;
cout << “Enter choice: “;
cin >> choice;
cin.ignore();//remove newline
switch(choice)
{
case 1:
inventory.listBooks();
break;
case 2:
inventory.listShoppingCart();
break;
case 3:
addBook(inventory);
break;
case 4:
removeBook(inventory);
break;
case 5:
inventory.checkOut();
break;
default:
cout << “Invalid menu choice!” << endl;
}
}
return 0;
}

void addBook(Inventory &inventory)
{
char title[250];
char ans;
int qty;
cout << “Which book would you like to add (type ‘p’ to see list of books)?” << endl;
cin.getline(title, 250);
if(strcmp(title, “p”) == 0)
{
inventory.listBooks();
cout << “Which book would you like to add? ” << endl;
cin.getline(title, 250);
}
int available = inventory.getNumCopies(title);
if(available == 0)
{
cout << “Sorry no copies of the book.” << endl;
return;
}
if(inventory.isBookInCart(title))
{
cout << “This book is already in your cart.” << endl;
cout << “Do you want to change the quantity? (y or n): ” ;
cin >> ans;
if(!(ans == ‘y’ || ans ==’Y’))
return;
}

cout << “How many copies? ” ;
cin >> qty;

while(qty < 0)
{
cout << “Can’t have zero or negative quantity. Please re-enter.” << endl;
cin >> qty;
}
while(qty > available)
{
cout << “Sorry we don’t have that many copies in stock. We have ” << available << ” available” << endl;
cout << “Please re-enter a quantity less than this.” << endl;
cin >> qty;
}

inventory.addBookToCart(title, qty);
cout << qty << ” copies of ” << title << ” added to your cart.” << endl;
inventory.showTotalPrice();
cout << endl;
}

void removeBook(Inventory &inventory)
{

char title[250];

cout << “Which book would you like to remove (type ‘p’ to see list of books)?” << endl;
cin.getline(title, 250);
if(inventory.removeBookFromCart(title))
cout << title << ” has been removed from your cart.” << endl;
else
cout << “Can’t find the title in inventory.” << endl;
cout << endl;
}

output

############## WELCOME TO OUR BOOKSTORE ##############

——– Menu ——–
1. List books to buy.
2. List Shopping cart.
3. Add book to cart.
4. Remove book from cart.
5. Checkout and quit.
Enter choice: 2
— Shopping Cart —
**Your Shopping Cart is Empty **
——– Menu ——–
1. List books to buy.
2. List Shopping cart.
3. Add book to cart.
4. Remove book from cart.
5. Checkout and quit.
Enter choice: 1
Title: Tweny Thousand Leagues Under the Sea
Author: Jules Verne
Count: 10
Price: 20.99
———————————
Title: A Tale of Two Cities
Author: Charles Dickens
Count: 15
Price: 15.99
———————————
Title: The House of the Seven Gables
Author: ‎Nathaniel Hawthorne
Count: 13
Price: 12.99
———————————
Title: Around the World in 80 Days
Author: Jules Verne
Count: 3
Price: 11.99
———————————
Title: Flatland: A Romance of Many Dimensions
Author: Edwin Abbott
Count: 18
Price: 8.99
———————————
Title: Alice in Wonderland
Author: Lewis Carroll
Count: 11
Price: 14.99
———————————
——– Menu ——–
1. List books to buy.
2. List Shopping cart.
3. Add book to cart.
4. Remove book from cart.
5. Checkout and quit.
Enter choice: 3
Which book would you like to add (type ‘p’ to see list of books)?
Alice in Wonderland
How many copies? -3
Can’t have zero or negative quantity. Please re-enter.
1000
Sorry we don’t have that many copies in stock. We have 11 available
Please re-enter a quantity less than this.
3
3 copies of Alice in Wonderland added to your cart.
Total before discount: $44.97
Discount is: 0.00
Total: $44.97

——– Menu ——–
1. List books to buy.
2. List Shopping cart.
3. Add book to cart.
4. Remove book from cart.
5. Checkout and quit.
Enter choice: 2
— Shopping Cart —
=>Item: Alice in Wonderland
Price per book: 14.99
Quantity: 3
—————————————-

Total before discount: $44.97
Discount is: 0.00
Total: $44.97

——– Menu ——–
1. List books to buy.
2. List Shopping cart.
3. Add book to cart.
4. Remove book from cart.
5. Checkout and quit.
Enter choice: 3
Which book would you like to add (type ‘p’ to see list of books)?
p
Title: Tweny Thousand Leagues Under the Sea
Author: Jules Verne
Count: 10
Price: 20.99
———————————
Title: A Tale of Two Cities
Author: Charles Dickens
Count: 15
Price: 15.99
———————————
Title: The House of the Seven Gables
Author: ‎Nathaniel Hawthorne
Count: 13
Price: 12.99
———————————
Title: Around the World in 80 Days
Author: Jules Verne
Count: 3
Price: 11.99
———————————
Title: Flatland: A Romance of Many Dimensions
Author: Edwin Abbott
Count: 18
Price: 8.99
———————————
Title: Alice in Wonderland
Author: Lewis Carroll
Count: 8
Price: 14.99
———————————
Which book would you like to add?
Around the World in 80 Days
How many copies? 9
Sorry we don’t have that many copies in stock. We have 3 available
Please re-enter a quantity less than this.
3
3 copies of Around the World in 80 Days added to your cart.
Total before discount: $80.94
Discount is: 0.05
Total: $76.89

——– Menu ——–
1. List books to buy.
2. List Shopping cart.
3. Add book to cart.
4. Remove book from cart.
5. Checkout and quit.
Enter choice: 2
— Shopping Cart —
=>Item: Alice in Wonderland
Price per book: 14.99
Quantity: 3
—————————————-
=>Item: Around the World in 80 Days
Price per book: 11.99
Quantity: 3
—————————————-

Total before discount: $80.94
Discount is: 0.05
Total: $76.89

——– Menu ——–
1. List books to buy.
2. List Shopping cart.
3. Add book to cart.
4. Remove book from cart.
5. Checkout and quit.
Enter choice: 3
Which book would you like to add (type ‘p’ to see list of books)?
Alice in Wonderland
This book is already in your cart.
Do you want to change the quantity? (y or n): y
How many copies? 6
6 copies of Alice in Wonderland added to your cart.
Total before discount: $170.88
Discount is: 0.10
Total: $153.79

——– Menu ——–
1. List books to buy.
2. List Shopping cart.
3. Add book to cart.
4. Remove book from cart.
5. Checkout and quit.
Enter choice: 2
— Shopping Cart —
=>Item: Alice in Wonderland
Price per book: 14.99
Quantity: 9
—————————————-
=>Item: Around the World in 80 Days
Price per book: 11.99
Quantity: 3
—————————————-

Total before discount: $170.88
Discount is: 0.10
Total: $153.79

——– Menu ——–
1. List books to buy.
2. List Shopping cart.
3. Add book to cart.
4. Remove book from cart.
5. Checkout and quit.
Enter choice: 1
Title: Tweny Thousand Leagues Under the Sea
Author: Jules Verne
Count: 10
Price: 20.99
———————————
Title: A Tale of Two Cities
Author: Charles Dickens
Count: 15
Price: 15.99
———————————
Title: The House of the Seven Gables
Author: ‎Nathaniel Hawthorne
Count: 13
Price: 12.99
———————————
Title: Around the World in 80 Days
Author: Jules Verne
Count: 0
Price: 11.99
———————————
Title: Flatland: A Romance of Many Dimensions
Author: Edwin Abbott
Count: 18
Price: 8.99
———————————
Title: Alice in Wonderland
Author: Lewis Carroll
Count: 2
Price: 14.99
———————————
——– Menu ——–
1. List books to buy.
2. List Shopping cart.
3. Add book to cart.
4. Remove book from cart.
5. Checkout and quit.
Enter choice: 4
Which book would you like to remove (type ‘p’ to see list of books)?
addd
Can’t find the title in inventory.

——– Menu ——–
1. List books to buy.
2. List Shopping cart.
3. Add book to cart.
4. Remove book from cart.
5. Checkout and quit.
Enter choice: 4
Which book would you like to remove (type ‘p’ to see list of books)?
Around the World in 80 Days
Around the World in 80 Days has been removed from your cart.

——– Menu ——–
1. List books to buy.
2. List Shopping cart.
3. Add book to cart.
4. Remove book from cart.
5. Checkout and quit.
Enter choice: 2
— Shopping Cart —
=>Item: Alice in Wonderland
Price per book: 14.99
Quantity: 9
—————————————-

Total before discount: $134.91
Discount is: 0.10
Total: $121.42

——– Menu ——–
1. List books to buy.
2. List Shopping cart.
3. Add book to cart.
4. Remove book from cart.
5. Checkout and quit.
Enter choice: 5
*** CHECKOUT ***
Final Total is: $121.42
Final discount is: 0.10
You saved: $13.49