Starting Computing Project 2

Description

All 3 components (Cloud9 workspace, Moodle Coderunner attempts, and zip file) must be completed and submitted by Saturday, March 23, at 6 pm for your homework to receive points.

Project 2 requires you to have an interview grading with your TA, completed by Monday, April 15 (Tax Day).

 

1. Objectives

• Define classes and create objects

• Array operations: initialization, search

• Create arrays of an object type

• Use filestream objects to read data from text files

 

2. Submission Requirements

All three steps must be fully completed by the submission deadline for your homework to be graded.

1. Create Project2 directory on your Cloud 9 workspace: ​Your recitation TA will review your code by going to your Cloud9 workspace. ​TAs will check the last version that was saved before the submission deadline​.

◦ Create a directory called ​Project2 and place all your file(s) for this assignment in this directory.

◦ Make sure to ​save the final version of your code (File > Save). Verify that this version displays correctly by going to File > File Version History.

◦ The file(s) should have all of your functions, test cases for the functions in main() function(s), and adhere to the style guide. Please read the submission file instructions under Week 4. ​You must include a test case for each one of your member functions for your classes.
2. Submit to the Moodle Coderunner: ​Head over to Moodle to the link ​Project 2 Coderunner​. You will find one programming quiz question for each problem in the assignment. Submit your solution for the first problem and press the Check button. You will see a report on how your solution passed the tests, and the resulting score for the first problem. You can modify your code and re-submit (press ​Check ​again) as many times as you need to, up until the assignment due date. Continue with the rest of the problems.

3. Submit a .zip file to Moodle: ​After you have completed all 9 questions from the Moodle assignment, zip all 15 files you compiled in Cloud9, and submit the zip file through the ​Project 2 (File Submission)​​link on Moodle.

 

 

3. Rubric

Aside from the points received from the ​Project 2 Coderunner quiz problems, your TA will look at your solution files (zipped together) as submitted through the ​Project 2 (File Submission)​link on Moodle and assign points for the following:

Style and Comments ​(5 points):
• The ​style guide​is posted on Moodle under Week 6.
• Your code should be well-commented. Please review the standard for well-commented code, presented in more detail in previous homework write-ups.

• Please also include a comment at the top of your solution with the following format:

◦ CS1300 Spring 2019

◦ Author: my name

◦ Recitation: 123 – Favorite TA

◦ Cloud9 Workspace Editor Link: https://ide.c9.io/…

◦ Project 2 – Problem # …

Global variables ​(use will result in a 5 point deduction):
• Later in the semester, we will learn about global variables and the joys and dangerous therein. To keep things simple, straightforward, and easy to debug and test, ​you may not use global variables in this homework.
Algorithm ​(5 points):
• Before each function that you define, you should include a comment that describes the inputs and outputs of your function and what algorithms you are using inside the function. Please review the standard for including your algorithm for each function, presented in more detail in previous homework write-ups.

Test Cases​:
• Test cases for Project 2 are not a part of the grade. However, we expect for you to write your own test cases or use examples in this write-up to test (and debug) your code. In the Coderunner, you are allowed to use up to 30 times to click “check” button without penalty. After 30 checks, points will be deducted.

Please make sure that your submission files follow the the ​submission file instructions under Week 6.

 

 

 

4. Problem Set

*All the examples and values used in examples are arbitrary and randomly generated.*

In Project 2, you will be creating a ​Library​class to handle the operation of your ​Book and ​User​classes from Homework 7. This new class will streamline the use of your previously-created classes, and will introduce the ability to recommend books based on the similarity between two users.

Specifications

• Create a new class ​Library​. Define the class in a header file and implement it in a separate cpp file.

• The ​Book​and ​User​classes from Homework 7 will be part of Project 2 as well. There may be some small modifications of your member functions and class definitions to fit the new ​Library ​class.

• In a driver routine called ​project2.cpp​, the ​main() ​function will create an instance of Library object and a menu as specified below.

• Students should have seven files (​Book.h​, ​Book.cpp​, ​User.h​, ​User.cpp​,
Library.h​, ​Library.cpp​, ​project2.cpp​)
• The name of each member function should be exactly as specified. If you modify the function names, then your solution will not pass the autograder.

• There are two questions in Coderunner: 1) Library class 2) driver function

4.1. Library Class

(150 points in Coderunner)

Problem 0 – ​Library​Class
Create ​Library.h and ​Library.cpp ​, and implement a class ​Library​, with separate interface and implementation, comprised of the following attributes:

 

Data members (private):

int: ​sizeBook
The capacity of the ​books​array (50). Constant
int: ​sizeUser
The capacity of the ​users​array (100). Constant
Book ​array: ​books
An array of ​Book​objects
User ​array: ​users
An array of ​User​objects
int: ​numBooks
Number of books in the database (library)
int: ​numUsers
Number of users in the database (library)
Member functions (public):

 

Default constructor
Sets both ​numBooks​and ​numUsers ​to value 0.
getSizeBook()
Returns ​sizeBook​as an integer
getSizeUser()
Returns ​sizeUser​as an integer
getNumBooks()
Returns ​numBooks​as an integer
getNumUsers()
Returns ​numUsers​as an integer
readBooks(string)
Takes a string (the name of the file to be read) and

populates the ​books​array. Returns the total

number of books in ​books​array as an integer
printAllBooks()
Prints all books stored in ​books​array.
readRatings(string)
Takes a string (the name of the file to be read) and

populates the ​users​array. Returns the total

number of users in ​users​array as an integer
getRating(string, string)
Takes two strings (username and book title) and

returns that user’s rating for the specified book.

getCountReadBooks(string)
Takes a string (username) and returns the number

of books read by that user as an integer.

viewRatings(string)
Takes a string (username) and prints ​all the books

a user has provided ratings for.

calcAvgRating(string)
Takes a string (the title of a book) and returns the

average rating of the specified book as a double

addUser(string)
Takes a string (username) and returns an integer​​1

if the user is successfully added, 0 if the username

already exists in the users array and -2 if the users

array is already full.

checkOutBook(string,
Takes two strings and an integer for username, title
string, int)
of book, and a new rating, respectively (in this

order). Returns an integer 1 if the rating is

successfully updated, -4 if the rating value is not

valid and -3 if the rating value is valid, but the user

or title does not exist in the database.

getRecommendations(string)
Takes a string username and prints the first 5 book

recommendations from the most similar (other)

user.

 

It is advisable to write your own test cases for each class. Test your class in Cloud9 before submitting to the autograder, because the CodeRunner autograder has a ​submission limit of 30 attempts​, after which there will be a small deduction of points.

Note that the following is broken up into problems to make it a bit more digestible, and for us to break up which parts are worth which points, but there are only 2 Coderunner problems on Moodle for testing your implementations.
Problem 1 – the member function ​readBooks

Update the ​readBooks function from Homework 7 to now be a member function for the Library class. The ​readBooks function populates an array of ​Book objects with the title and author data found in a file similar to the file ​books.txt ​that you’ve used in previous assignments. The array of ​Book objects is one of the data members of the ​Library ​class. This function should:

• Accept one input argument:

◦ string​: the name of the file to be read
• Use ​ifstream and ​getline to read data from the file, making an instance of the ​Book​object for each line, and placing it into the ​books​array.

• Return the total number of books in the system, as an integer.

• If multiple txt files are read, then the ​books​array should be populated with all of the books from all of the files (unless it reaches capacity, of course). For example, suppose ​readBooks​reads ​books1.txt​, and then it reads books2.txt​. After the second function call, ​readBooks​returns the total number of books read from ​both​files, and the ​books​array stores all books from both ​books1.txt​and​ books2.txt​.

• The function should return the following values depending on cases:

◦ Return the total number of ​books​in the system, as an integer.
◦ When the file is not opened successfully, return -1.

◦ When ​numBooks​is equal to the ​size​, return -2.
◦ The priority of the return code -2 is higher than -1, i.e., in cases when numBooks is equal to the ​sizeBook ​and the file cannot be opened, the function should return -2.

◦ When ​numBooks is smaller than ​sizeBook​, keep the existing elements in books​, then read data from the file and add (append) the data to the array. ​Be sure to update the total number of books in the system. The number of books stored in the array cannot exceed the ​sizeBook of the books ​array.

• Empty lines should not be added to the arrays.

Important​: Since your ​books array is private, we cannot directly check objects stored in the array form the ​main() ​, like you tested in Homework 7. Let’s make printAllBooks to check if your ​readBooks are working fully functionally… in the next problem!
Example 1:​​readBooks​as a general case

fileName.txt
Author A,Book 1

Author B,Book 2
Function calls
// make
library object

Library
myLibrary

// call
readBooks

int rv = myLibrary.readBooks(“fileName.txt”);

// print values

cout <<
“rv = “ << rv << endl;

cout <<
“numBooks = “;

cout <<
myLibrary.getNumBooks() << endl;

// print books

myLibrary.printAllBooks();
Output
rv = 2

numBooks = 2

Here is a list of books

Book 1 by Author A

Book 2 by Author B

Example 2: Suppose we call the ​readBooks functions twice. In ​books array, all books from the first file and the second file should be stored in the ​books array, and the function returns the total number of the books stored in the ​books​array.

book1.txt
Author A,Book 1

Author B,Book 2
book2.txt
Author C,Book 3

Author D,Book 4
Function calls
// make library object

Library myLibrary

// call readBooks and check return values

int rv1 = myLibrary.readBooks(“book1.txt”);

cout << “rv1 = “ << rv << endl;

int rv2 = myLibrary.readBooks(“book2.txt”);

cout << “rv2 = “ << rv << endl;

// check value of getNumBooks

cout << “numBooks = “;

cout << myLibrary.getNumBooks() << endl;

// print books

myLibrary.printAllBooks();
Output
rv1 = 2

rv2 = 4

numBooks = 4

Here is a list of books

Book 1
by Author A

Book 2
by Author B

Book 3
by Author C

Book 4
by Author D

Example 3:​file does not exist.

Function call
// make
library object

Library
myLibrary

// call
readBooks and check return values

int rv1 = myLibrary.readBooks(“badFile.txt”);

cout << “rv1 = “ << rv << endl;
Output
rv1 = -1

Example 4: ​numBooks becomes equal to the ​sizeBook and the function returns the sizeBook​.

book1.txt
Author A,Book 1

Author B,Book 2

Author C,Book 3

Function call
// make
library obj

Library
myLibrary

// multiple files
were read

// check value of
getNumBooks

cout <<
“numBooks
= “;

cout <<
myLibrary.getNumBooks() << endl;

// call
readBooks
and check return values

int rv1
= myLibrary.readBooks(“book1.txt”);

cout <<
“rv1 = “ << rv << endl;

 

 

// check value of getNumBooks

cout << “numBooks = “;

cout << myLibrary.getNumBooks() << endl;

// print books

myLibrary.printAllBooks();
Output
numBooks = 48

rv1 = 50

numBooks = 50

Here is a list of books

(48 other books….)

Book 1 by Author A

Book 2 by Author B

Example 5: ​numBooks is equal to the ​sizeBook means that the array is already full and it returns -2.

fileName.txt
Author A,Book 1

Author B,Book 2

Author C,Book 3

Function call
// make
library obj

Library
myLibrary

// multiple files
were read

// check value of
getNumBooks

cout <<
“numBooks
= “;

cout <<
myLibrary.getNumBooks() << endl;

// call
readBooks
and check return values

int rv1
= myLibrary.readBooks(“book1.txt”);

cout <<
“rv1 = “ << rv << endl;

// check value of
getNumBooks

cout <<
“numBooks
= “;

cout <<
myLibrary.getNumBooks() << endl;
Output
numBooks = 50

rv1 = -2

 

numBooks = 50

 

 

Problem 2 – the member function ​printAllBooks

The ​printAllBooks function from Homework 7 was very useful. We can use this function to test your ​readBooks function. So let’s do it again. Write a ​new ​printAllBooks ​function, which will be a member function of the ​Library class, and will be useful in displaying the contents of your library.

• This function should not take any arguments.

• This function does ​not​return anything
● This function should print ​“Here is a list of books” and then each book in a new line using the following statement

cout << books[i].getTitle() << ” by “; cout << books[i].getAuthor() << endl;

Note: In the test case, you can always assume that the number of books matches the number of elements in the ​books​array.

Expected output ​(assuming you have read the data from ​books.txt​)

Here is a list of books

The Hitchhiker’s Guide To The Galaxy by Douglas Adams Watership Down by Richard Adams

The Five People You Meet in Heaven by Mitch Albom Speak by Laurie Halse Anderson …

 

Problem 3 – the member function ​readRatings

Update the ​readRatings function from Homework 7 to now be a member function for the Library class. The ​readRatings function populates an array of ​User objects with the username and ratings data found in a file similar to the file ​ratings.txt ​that you’ve used in previous assignments. Each username is followed by a list of ratings of the user for each book in ​books.txt​. The array of ​User objects is one of the data members of the ​Library class.

For example, suppose there are a total of 3 books. The ​ratings.txt file would be of the format:

ratings.txt

ritchie,3,3,3

stroustrup,0,4,5

gosling,2,2,3

rossum,5,5,5

…

 

This function should:

• Accept one input argument:

◦ string​: the name of the file to be read
• Use ​ifstream and ​getline to read data from the file, making an instance of a User​object for each line, and placing it in the ​users ​array.

• Hint​: You can use the ​split() – function from Problem 3 in Homework 6, with comma (“,”) as the delimiter.

• You can use ​stoi to convert each rating value (a string, as read from the text file) into an integer value.

• If multiple txt files are read, then the ​users​array should be populated with all of the user data from all of the files (unless it reaches capacity, of course). For example, suppose ​readRatings​reads ​ratings1.txt​, and then it reads ratings2.txt​. After the second function call, ​readRatings​returns the total number of users read from ​both​files, and the ​users​array stores all users from both​​ratings1.txt​and ​ratings2.txt

• The function should return the following values depending on cases:

◦ Return the total number of users in the system, as an integer.

◦ If the file cannot be opened, return -1

◦ When ​numUsers​is greater than or equal to the ​sizeUser​, return -2
◦ The priority of the return code -2 is higher than -1, i.e., in cases when numUsers is equal to the ​sizeUser ​and the file cannot be opened, the function should return -2

◦ When ​numUsers is smaller than the ​sizeUser of ​users array, keep the existing elements in ​users array, then read data from file and add (append) the data to the arrays. ​Be sure to update the total number of users in the system. The number of users stored in the arrays cannot exceed the size of the ​users ​array.

• Empty lines should not be added to the arrays.
Important​: Since your ​users array is private, we cannot directly check objects stored in the array from the ​main()​, like you tested in Homework 7. Let’s make ​getRating (in the next problem!) to check if your ​readRatings​are working well.

Example 1: ​​readRatings​as a general case

bookFile.txt
AuthorA,Book1

AuthorB,Book2

AuthorC,Book3

AuthorD,Book4

AuthorF,Book5
ratingFile.txt
Ninja,0,1,2,3,4

Myth,2,2,4,5,1

Sphyer,3,1,0,0,5

Daequan,0,0,0,0,2
Function call
// make
library obj

Library
lib;

// read
book file

lib.readBooks(“bookFile.txt”);

// call readRatings and check return values

int rv1
= lib.readRatings(“ratingFile.txt”);

cout <<
“rv1 = ”;

cout <<
rv1 << endl;

// check value of getNumUsers

cout <<
“numUsers = “;

cout <<
lib.getNumUsers() << endl;

// print user’s ratings

string name = “Ninja”

cout <<
lib.getRating(name, “book1”) << endl;

cout <<
lib.getRating(name, “book2”) << endl;

cout <<
lib.getRating(name, “book3”) << endl;

cout <<
lib.getRating(name, “book4”) << endl;

cout <<
lib.getRating(name, “book5”) << endl;
Output
rv1 = 4

numUsers = 4

0

1

2

3

4

 

Example 2: Suppose we call the ​readRatings functions twice. In ​users array, all users from the first file and the second file should be stored in the ​users array, and the function returns the total number of the users stored in the ​users​array.

ratingFile​.txt
Ninja,0,1,2,3,4

Myth,2,2,4,5,1

Sphyer,3,1,0,0,5

Daequan,0,0,0,0,2
ratingFile2​.txt
alpha,0,1,2,3,4

Beta,1,2,3,4,0

gamma,3,4,0,1,2

delta,2,3,4,0,1

sigma,4,0,1,2,3
Function calls
// make library obj

Library lib

// call readRatings and check return values

int rv1 = lib.readRatings(“ratingFile.txt”);

cout << “rv1 = “ << rv << endl;

int rv2 = lib.readRatings(“ratingFile2.txt”);

cout << “rv2 = “ << rv << endl;

// check value of getNumBooks

cout << “numUsers = “;

cout << lib.getNumUsers() << endl;
Output
rv1 = 4

rv2 = 9

numUsers = 9

 

Example 3:​file does not exist.

Function call

• make library obj Library myLibrary

// call readBooks and check return values

int rv1
= myLibrary.readRatings(“badFile.txt”);

cout <<
“rv1 = “ << rv << endl;
Output
rv1 = -1

Example 4:​​numUsers​equals ​sizeBook​means the array is already full.

ratingFile​.txt
Ninja,0,1,2,3,4

Myth,2,2,4,5,1

Sphyer,3,1,0,0,5

Daequan,0,0,0,0,2
Function call
// make
library obj

Library
myLibrary

// multiple files were read

// check value of getNumUsers

cout <<
“numUsers = “;

cout <<
myLibrary.getNumUsers() << endl;

// call
readRatings and check return values

int rv1
=

myLibrary.readRatings(“ratingFile.txt”);

cout <<
“rv1 = “ << rv1 << endl;

// check value of getNumUsers

cout <<
“numUsers = “;

cout <<
myLibrary.getNumUsers() << endl;

// call
readRatings again

int rv2
=

myLibrary.readRatings(“ratingFile.txt”);

cout <<
“rv2 = “ << rv2 << endl;
Output
numUsers = 98

rv1 = 100

numUsers = 100

rv2 = -2

 

Problem 4 – the member function ​getRating

The member function ​getRating accepts the given a user’s name and a book’s title, and returns the rating that the user gave for that book.
• Your function MUST be named ​getRating​.

• Your function should take 2 input arguments in the following order:

◦ string​: username
◦ string​: title of the book

• The username and book title search should be case insensitive. For example, “Ben, “ben” and “BEN” are one and the same user.

• If both the user name and the book title are found, then the function should return the user’s rating value for that book title.

• The function should return the following values depending on cases:

◦ Return the rating value if both user and title are found

◦ Return -3 if either the user or the title are not found

Set up for the examples below

bookFile.txt
Author1,Title1

Author2,Title2

Author3,Title3
ratingFile.txt
User1,1,4,2

User2,0,5,3

//Create a new Library

Library myLibrary;

//add books to Library

myLibrary.readBooks(“bookFile.txt”);

//add users to Library

myLibrary.readRatings(“ratingFile.txt”);

Example 1: Both the ​userName and ​bookTitle exists, and the value of rating is non-zero, returns the value of the given user’s rating for the given book

Function call
getRating(“User1”, “Title2”);
Return value
4

 

Example 2:​The ​userName​does not exist, it returns – 3

Function call
getRating(“User4”, “Title1”);

Return value
-3

 

Example 3:​The ​bookTitle​does not exist, it returns – 3

Function call
getRating(“User1”, “Title10”);

Return value
-3

 

 

Example 4:​The ​userName​and the ​bookTitle​do not exist, returns -3

Function call
getRating(“User12”, “Title10”);
Return value
-3

 

 

Problem 5 – the member function ​getCountReadBooks

The member function ​getCountReadBooks which determines how many books a particular user has read and reviewed. This function should:

• Accept one argument:

◦ string​: username
• The username and book title search should be case insensitive. For example, “Ben, “ben” and “BEN” are one and the same user.

• The function should return the following values depending on cases:

◦ Return the number of books read/reviewed by the specified user if user is found

◦ Return -3 if the username is not found

Example 1​: The library is initialized

bookFile.txt
Author1,Title1

Author2,Title2

Author3,Title3
ratingFile.txt
User1,1,4,2

User2,0,5,3

User3,0,0,0
Function calls
//Create a new Library

 

 

 

 

 

 

 

 

outputs

Library myLibrary;

//add books to Library myLibrary.readBooks(“bookFile.txt”);

//add users

myLibrary.readRatings(“ratingFile.txt”);

// viewRatings for User2

cout << myLibrary.getCountReadBooks(“User2”);

2

 

Example 2​: The user does not exist

bookFile.txt
Author1,Title1

Author2,Title2

Author3,Title3
ratingFile.txt
User1,1,4,2

User2,0,5,3

User3,0,0,0
Function calls
//Create a new Library

Library myLibrary;

//add books to Library

myLibrary.readBooks(“bookFile.txt”);

//add users

myLibrary.readRatings(“ratingFile.txt”);

cout << myLibrary.getCountReadBooks(“User4”);
outputs
-3

 

Example 3​: The user has not rated any book yet

bookFile.txt

Author1,Title1

Author2,Title2

Author3,Title3

ratingFile.txt
User1,1,4,2

User2,0,5,3

User3,0,0,0
Function calls
//Create a new Library

Library myLibrary;

//add books to Library

myLibrary.readBooks(“bookFile.txt”);

//add users

myLibrary.readRatings(“ratingFile.txt”);

// getCountReadBooks for User3

cout << myLibrary.getCountReadBooks(“User3”);
outputs
0

 

 

Problem 6 – the member function ​viewRatings

Create a new member function ​viewRatings​prints​ all the books a user has provided ratings for. Recall that a rating a book 0 means a user has not rated that book and hence shouldn’t be displayed. This function should:

• Accept one input argument:

◦ string​: username
• Not return anything.

• If the user is not found in the database, print:

<username> does not exist.

• If the user is found in the database, but has not rated any books, print:

<username> has not rated any books yet.

• If the user exists in the database, and has rated at least one book, display the user’s ratings in the following format:

Expected output ​(assuming you have read the data ​only​from books.txt,ratings.txt​)

Here are the books that megan rated

Title : The Hitchhiker’s Guide To The Galaxy

Rating : 5

—–

Title : The Five People You Meet in Heaven

Rating : 2

—–

(…)

 

Example 1​: The library is initialized

bookFile.txt
Author1,Title1

Author2,Title2

Author3,Title3
ratingFile.txt
User1,1,4,2

User2,0,5,3

User3,0,0,0
Function calls
//Create a new Library

Library myLibrary;

//add books to Library

myLibrary.readBooks(“bookFile.txt”);

//add users

myLibrary.readRatings(“ratingFile.txt”);

myLibrary.viewRatings(“User2”);
outputs
Here are the books that User2 rated

Title : ​Title2

Rating : 5

—–

Title : ​Title3

Rating : 3

—–

 

Example 2​: The user has not rated any book yet

bookFile.txt

Author1,Title1

 

Author2,Title2

 

Author3,Title3

ratingFile.txt
User1,1,4,2

 

User2,0,5,3

 

User3,0,0,0

Function calls
//Create a new
Library

Library myLibrary;

//add books to
Library

myLibrary.readBooks(“bookFile.txt”);

//add users

 

myLibrary.readRatings(“ratingFile.txt”);

myLibrary.viewRatings(“User3”);

outputs
User3 has not rated any books yet.

 

Example 3​: The user does not exist

bookFile.txt
Author1,Title1

 

Author2,Title2

 

Author3,Title3

ratingFile.txt
User1,1,4,2

 

User2,0,5,3

 

User3,0,0,0

Function calls
//Create a new
Library

Library myLibrary;

//add books to
Library

myLibrary.readBooks(“bookFile.txt”);

//add users

 

myLibrary.readRatings(“ratingFile.txt”);

myLibrary.viewRatings(“User4”);

outputs
User4 does not
exist.

 

 

Problem 7 – the member function ​calcAvgRating

The member function ​calcAvgRating returns the average (mean) rating for a particular book. This function should:

• Accept one argument:

◦ string​: book title
• The book title search should be case insensitive. For example, “Ben, “ben” and “BEN” are one and the same user.

• The average rating is calculated by the sum of non-zero rating values divided by the number of non-zero ratings.

• The function should return the following values depending on cases:

◦ Return the average rating of the specified book as a ​double​if title is found

◦ Return -3 if title is not found

◦ Return 0 if the book has not been read by anyone. Poor book!

Note: Books that haven’t been read (have a rating value of 0) ​shouldn’t ​be counted in calculating the average.

Example 1​: The library is initialized, and we can calculate an average ratings for the book.

bookFile.txt
Author1,Title1

Author2,Title2

Author3,Title3
ratingFile.txt
User1,1,4,2

User2,0,5,3

User3,0,0,0
Function calls
//Create a new Library

Library myLibrary;

//add books to Library

myLibrary.readBooks(“bookFile.txt”);

//add users

myLibrary.readRatings(“ratingFile.txt”);

// calcAvgRating for Title2

cout << myLibrary.calcAvgRating(“title2”);

 

outputs

4.5

The function returns 4.5 because User 1 rated 4 and User 2 rated 5, which means (4 + 5) / 2 = 4.5. Since User 3’s rating is 0, it is not included for the calculation.

Example 2​: The title does not exist in the library. No user has read a particular title

bookFile.txt
Author1,Title1

Author2,Title2

Author3,Title3
ratingFile.txt
User1,0,4,2

User2,0,5,3

User3,0,0,0
Function calls
//Create a new Library

Library myLibrary;

//add books to Library

myLibrary.readBooks(“bookFile.txt”);

//add users

myLibrary.readRatings(“ratingFile.txt”);

// calcAvgRating for Title4

cout << myLibrary.calcAvgRating(“Title4”);

// calcAvgRating for Title1

cout << myLibrary.calcAvgRating(“Title1”);
outputs
-3

0

 

Problem 8 – the member function ​addUser

The member function ​addUser​adds a new user to the database. This function should:
• Accept one argument:

◦ string​: user name
• The user name is case insensitive (e.g. Ben. BEN, ben are all same as ben)

• Fill in the ​username​and​ ratings​data members for a ​User​object, at the first unused position in the array of ​User​objects.
• Be sure to update the total number of users in the system

• The function returns following one of the following integer values:

◦ Return 1 if the user is successfully added.

◦ Return 0 if the username already exists in the ​users​array.
◦ Return -2 if the ​users​array is already full.

Example 1​: Successfully user is added to the ​users​array.

ratingFile.txt
User1,1,4,2

User2,0,5,3

User3,0,0,0
Function calls
//Create a new Library

Library myLibrary;

myLibrary.readRatings(“ratingFile.txt”);

// checking the user count

cout << “numUsers = ” << myLibrary.getNumUsers()

<< endl;

//add users

cout << myLibrary.addUser(“User4”);

// checking the user count

cout << “numUsers = ” << myLibrary.getNumUsers()

<< endl;
outputs
numUsers = ​3

1

numUsers = ​4

Note that at this point, there are 4 users in the system​, ​and User3 and User4 both have all 0 ratings associated with them.

Example 2​: The username already exists in the users array (and is case-insensitive)

ratingFile.txt
User1,1,4,2

User2,0,5,3

User3,0,0,0
Function calls
//Create a new Library

Library myLibrary;

 

 

 

 

outputs

//add users

myLibrary.readRatings(“ratingFile.txt”);

//add users

cout << myLibrary.addUser(“user2”);

0

Example 3​: The ​users​array is full

Function calls
//Create a new Library

Library myLibrary;

//add books to Library

myLibrary.readBooks(“bookFile.txt”);

//add users

myLibrary.readRatings(“100UsersFile.txt”);

// check value of getNumBooks

cout << “numUsers = “;

cout << myLibrary.getNumUsers() << endl;

// add users

cout << myLibrary.addUser(“user4”);
outputs
numUsers = 100

-2

 

Problem 9 – the member function ​checkOutBook

The member function ​checkOutBook​updates the rating of the book for the user. This function should:

• Accept three arguments in this order

◦ string​: username
◦ string​: book title

◦ int​: new rating
• Find the index of the user and the index for the book, then update the new rating if the new rating value is valid. The​ rating scheme follows the one provided in homework 6.

Rating
Meaning

0
Did not read

1
Hell No – hate it!!

2
Don’t like it.

3
Meh – neither hot nor cold

4
Liked it!

5
Mind Blown – Loved it!

 

• The username and book title search should be case insensitive. For example, “Ben, “ben” and “BEN” are one and the same user.

• The function returns the following integer value depending the cases (with the following order of precedence):

◦ Return 1 if the rating is successfully updated

◦ Return -4 if the rating value is not valid

◦ If the rating value is valid, but the user or title do not exist in the database, this function should return -3.

Set up for the examples below

bookFile.txt
Author1,Title1

Author2,Title2

Author3,Title3
ratingFile.txt
User1,1,4,2

User2,0,5,3

User3,0,0,0
Set up
//Create a new Library

Library myLib;

myLib.readBooks(“bookFile.txt”);

myLib.readRatings(“ratingFile.txt”);
Example 1​: User successfully checks out a book and updates an existing rating.

Set up
int oldRating = myLib.getRating(“User2”, “Title1”);

int rv = myLib.checkOutBook(“User2”, “Title1”, 2);

int newRating = myLib.getRating(“User2”, “Title1”);

cout << “rv = “ << rv << endl;

cout << “oldRating = “ << oldRating << endl;

cout << “newRating = “ << newRating << endl;

outputs
rv = 1

oldRating = 0

newRating = ​2
Example 2​: The
rating value is invalid

Set up
int oldRating = myLib.getRating(“User2”, “Title1”);

int rv = myLib.checkOutBook(“User2”, “Title1”, 10);

int newRating = myLib.getRating(“User2”, “Title1”);

cout << “rv = “ << rv << endl;

cout << “oldRating = “ << oldRating << endl;

cout << “newRating = “ << newRating << endl;

outputs
rv = -4

oldRating = 0

newRating = ​0

 

Since the rating value is invalid, User2’s Title1 rating should stay the same.

 

Example 3​: title is not found

Function calls int rv = myLib.checkOutBook(“User2”, “noTitle”, 1);

cout << “rv = “ << rv << endl;
outputs

rv = -3

 

Example 4​: user is not found

Function calls int rv = myLib.checkOutBook(“noUser”, “title1”, 2); cout << “rv = “ << rv << endl;
outputs
rv = -3

 

 

Problem 10 – the member function ​getRecommendations

The member function ​getRecommendations​will​ recommend book titles a user might enjoy, based on the book ratings of another user who likes similar books. This function should:

• Accept one input argument:

◦ string​: username
• Not return anything.

• Find the user with the given username, and print some book recommendations to the screen. (Details on how to recommend books are given below.)

• The username search should be case insensitive. For example, “Ben, “ben” and “BEN” are one and the same user.

• If the user name is not found, it should print the following message :

<username> does not exist.

● If​​there are no books to recommend for the user, print the following:

There are no recommendations for <username> at present.
• If there is at least one book to recommend for a certain user, print the following information for at most five books:

Here is the list of recommendations <book_title_1> by <author1> <book_title_2> by <author2>

…

…

<book_title_5> by <author5>
How to find books to recommend?

The recommendations for a given user will be based on the other user who is most similar to that user. To generate recommendations, for example, for a user named Ben:

1. Find the most similar user to Ben. Let’s say we found Claire to be most similar.

2. Recommend to Ben the first 5 books in the database Claire has rated with a rating of 3, 4 or 5, that Ben has not yet read (rating 0).

3. If there are fewer than 5 books to recommend, recommend as many as possible. Ben will be presented with between 0 and 5 recommendations.

In order to compare two users and calculate their similarity, we will be looking at the rating values for all the books for ​both ​users (regardless of whether a user has read a book or not), and calculating the difference in their ratings. Because our similarity metric is based on difference, more similar users will have ​smaller ​similarity values​. Therefore, when Ben is compared to all other users in the database, the user whose similarity score with Ben is ​smallest​will be the most similar user (Claire).

Note 1: ​A new user, who has not rated any books, cannot be chosen as the most similar user. The ​getCountReadBooks function can be used to weed out the new users.

Note 2: ​In the event of a tie between two users for being the most similar to the user you are making recommendations for, make recommendations using the user with the lower​index within the users array.

The similarity metric you should use is the ​sum of squared differences (SSD)​. The sum of squared differences is calculated by summing the squares of the differences between corresponding elements in two ratings arrays from two users. Follow the example below.

Let ​A​represent ben’s ratings, and ​B​represent claire’s ratings.
A​is ben’s rating for book ​i​, and ​B​is claire’s rating for book ​i
i ​ i ​

 

 

 

Example 1 : Calculating SSD

john′s ratings : [0, 1, 3, 5]
claire′s ratings : [3, 0, 5, 0]

SSD=(0−3)2 +(1−0)2+(3−5)2+ (5−0)2
SSD = (−3)2 + (1)2 + (−2)2 + (5)2

SSD=9+1+4+25=39

Example 2: Users with very different ratings will get a high SSD.

john′s ratings : [5, 1, 0, 0, 5]

david′s ratings : [1, 5, 0, 5, 1]

SSD=(5−1)2 +(1−5)2+(5−0)2+(5−1)2
SSD= 42 +42+52+42

SSD=16+16+25+16= 73

Example 3: Two users with very similar ratings will get a low SSD.

john′s ratings : [5, 0, 5, 3]

claire′s ratings : [5, 0, 4, 2]

SSD = (5 −5)2 + (5 − 4)2+ (3 − 2)2
SSD=02+12+ 12

SSD=0+1+1=2

For example (this example is different than the data in ratings.txt):

Let’s say we’re generating recommendations for John. Here are the books:

Douglas Adams,The Hitchhiker’s Guide To The Galaxy Richard Adams,Watership Down

Mitch Albom,The Five People You Meet in Heaven Laurie Halse Anderson,Speak

Liz: [5, 1, 5, 3]

John: [5, 0, 3, 0]

David: [4, 1, 0, 5]

To generate recommendations for John:

1. find the most similar user

John has a SSD of 14 with Liz, and an SSD of 36 with David, so John is more similar to Liz. Thus, our book recommendations will be based on Liz’s ratings.

2. find 5 books Liz (the most similar user) has rated as a 3, 4, or 5 that John has not yet read (rating 0)

We look at Liz’s ratings to find books that she has rated that John has not:

◦ Liz has rated ​The Hitchhiker’s Guide To The Galaxy as​ 5, but John has already rated this book.

◦ Liz has rated Watership Down ​as 1​. ​John hasn’t read that book yet, but the rating value of 1 is lower than 3, so we ​do not add it to the list of recommendations.

◦ Liz has rated The Five People You Meet in Heaven as 5, but John has already rated this book.

◦ Liz has rated Speak ​as 3. John has not yet read that book, so we add it to the list of recommendations.

◦ There are no more books that Liz has rated, so we’re done. Our final list of recommendations will be:

Speak by Laurie Halse Anderson

 

Set-up for the examples:

bookFile.txt
Author1,Title1

Author2,Title2

Author3,Title3

Author4,Title4

Author5,Title5
ratingFile.txt
User1,5,4,2,3,1

User2,5,5,3,2,0

User3,0,0,0,0,0

User4,0,0,0,0,0

User5,5,0,2,3,0
Set-up
//Create a new Library

Library myLib;

myLib.readBooks(“bookFile.txt”);

myLib.readRatings(“ratingFile.txt”);

 

Example 1​: There are books to recommend

Function call
myLib.getRecommendations(“User5”);
outputs
Here are the list
of recommendations

Title2 by Author2

The best matched user for User5 is User1, with SSD = 17. Title2 is the only book to recommend because that is the only book User5 has not rated and User1 rated at least a 3.

Example 2​: No books to recommend

Function call
myLib.getRecommendations(“User2”);
outputs
There are no recommendations for User2 at present

 

The best matched user for User2 is User1, with SSD = 4. The only book User2 has not read is Title5, but it cannot be recommended because User2 rated it as 1. Hence, no books to recommend.

Example 3​: The most similar user has not rated any book. So need to find the second most similar user

Function call
myLib.getRecommendations(“User4”);
outputs
Here are the list of recommendations

Title1 by
Author1

Title4 by
Author4

The SSD score between User4 and User3 is 0. However, since the User3 has not rated any books, we need to find the other most similar user. The best matched user for User4 is User5, with SSD = 38. We will recommend Title1 and Title4.

4.2. Driver

(30 points in codeRunner)

Problem 11 – Driver function

Now, let’s modify our ​HW7.cpp from Homework 7 to use the ​Book class, ​User class, and Library class we have updated/created for Project 2. Make a copy of your old HW7.cpp
and rename it to ​project2.cpp​, to modify for this problem so we can show off to our enemies how much cool stuff we’re doing!

Since we’ve added some other functionality to our driver routine, we will need to update some of the menu functionality. Download the ​Project2Template.cpp​to update your displayMenu​function, as well as some other print statements.

The zip file submission should have five files for this problem: ​Book.h​, ​Book.cpp​, User.h​, ​User.cpp, Library.h​, ​Library.cpp​, and a driver called ​project2.cpp​, with a main() function to test your menu interface. Note that the submitted project2.cpp file should ​not have the class definitions in it. They should be contained in their respective modules (Book.h+Book.cpp, User.h+User.cpp, Library.h+Library.cpp, ) and ​#include​’ed in project2.cpp.

For ​Coderunner​, however, paste your entire project2.cpp driver function ​with the class definitions. You need to submit the the entire program project2.cpp, including the Book, User, and Library classes, in the answer box of the Coderunner auto-grader on Moodle.

The menu will run on a loop, continually offering the user eleven options until they opt to quit. You need to fill in the code for each of the options. You should make use of the functions you wrote previously, call them, and process the values they return.

• Option 1: ​Initialize library
◦ Prompt the user for a file name.

◦ Pass the file name to your ​readBooks​function.
◦ Print the total number of books in the database in the following format:

▪ Total books in the database: <numberOfBooks>

◦ If the function returned -1, then print the following message:

▪ No books saved to the database.

◦ If the function returned -2, print

▪ Database is already full. No books were added.

◦ When ​numBooks​is equal to size of the array print the following message:
▪ Database is full. Some books may have not been added.

• Option 2: ​Initialize user catalog
◦ Prompt the user for a file name.

◦ Pass the file name to your ​readRatings​function
◦ Print the total number of users in the database in the following format:

▪ Total users in the database: <numUsers>

◦ If the function returned -1, then print the following message:

▪ No users saved to the database.

◦ If the function returned -2, print

▪ Database is already full. No users were added.

◦ When ​numUsers​is equal to size of the array print the following message:
▪ Database is full. Some users may have not been added.

• Option 3: ​Display library
◦ If the database has not been initialized (i.e., arrays of books and users/ratings have not yet both been read in), then print

▪ Database has not been fully initialized.

◦ Otherwise, call your ​printAllBooks​function.

• Option 4: ​Get a rating
◦ If the database has not been initialized, print

▪ Database has not been fully initialized.

◦ Otherwise:

▪ Prompt the user for a username.

▪ Prompt the user for a title

▪ Pass the username and the title to your ​getRating​function

◦ If the user exists in the system, print the result in the following format:

▪ <name> rated <title> with <rating>

◦ If the function returns 0, print the result in the following format:

▪ <name> has not rated <title>

◦ If the function returns -3, print the result in the following format:

▪ <name> or <title> does not exist.

• Option 5: ​Get number of books the user has rated
◦ If the database has not been initialized, print

▪ Database has not been fully initialized.

◦ Otherwise:

▪ Prompt the user for a username.

▪ Pass the username to your ​getCountReadBooks​function

◦ If the user exists in the system and has rated some books:

▪ <name> rated <number> books.

◦ If the function returns 0, print the result in the following format:

▪ <name> has not rated any books.

◦ If the function returns -3, print the result in the following format:

▪ <name> does not exist.

• Option 6: ​View user’s ratings
◦ If the database has not been initialized, print

▪ Database has not been fully initialized.

◦ Otherwise:

▪ Prompt the user for a username.

▪ Pass the username to your ​viewRatings​function

• Option 7: ​Calculate the average rating for the book
◦ If the database has not been initialized, print

▪ Database has not been fully initialized.

◦ Otherwise:

▪ Prompt the user for a title.

▪ Pass the title to your ​calcAvgRating​function

◦ If the title exists in the system, display the average ratings in two decimal places:

▪ The average rating for <title> is <avg rating>

◦ If the function returns -3, print the result in the following format:
▪ <title> does not exist.

• Option 8: ​Add a user to the database.
◦ Prompt the user for a username.

◦ Pass the username to your ​addUser​function

◦ If the user is successfully added (the function returns 1), the print

▪ Welcome to the library <username>

◦ If the username exists in the system (the function returns 0), print

▪ <username> already exists in the database.

◦ If the function returns -2, print the result in the following format:

▪ Database is already full. <username> was not added.
• Option 9: ​Check out the book
◦ If the database has not been initialized, print

▪ Database has not been fully initialized.

◦ Otherwise:

▪ Prompt the user for a username.

▪ Prompt the user for a title.

▪ Prompt the user for a new rating.

▪ Pass the username, title, and rating to your ​checkOutBook function

◦ If the user is successfully added (the function returns 1), the print

▪ We hope you enjoyed your book. The rating has been updated.

◦ If the function returns -4, print:

▪ <rating> is not valid.

◦ If the function returns -3, print:

▪ <name> or <title> does not exist.

• Option 10: ​get recommendations
◦ If the database has not been initialized, print
▪ Database has not been fully initialized.

◦ Otherwise:

▪ Prompt the user for a username.

▪ Pass the username to your ​getRecommendations​function

• Option 11: ​Quit
◦ Print ​“good bye!”​before exiting

 

5. Project 2 checklist

Here is a checklist for submitting the assignment:
1. Complete the code ​Project 2 Coderunner
2. Submit one zip file to ​Project 2 (File Submission)​. The zip file should be named, <firstName>_<lastName>_project2.zip​., and have following 7 files:

1. Book.h

2. Book.cpp

3. User.h

4. User.cpp

5. Library.h

6. Library.cpp

7. project2.cpp

3. Sign up to the interview grading slot on Moodle. Please make sure that you sign-up and complete an interview grading with your TA by ​Monday, April 15​. The schedulers for interview grading will be available after the deadline of this project.

You are allowed to reschedule an interview grading session without any penalty once during the semester. If you miss a second time, you may reschedule but there will be a 25-point (out of 100) penalty, then 50 points for the third time.

 

6. Project​​2 point summary

Criteria

Pts

Coderunner

Interview grading

Style and Comments

Algorithms

Recitation attendance (Mar 19 or Mar 21)*

Not using Library class in the driver

Using global variables

Total

180

60

5

5

-50

-30

-5

250

* If your attendance is not recorded, you will lose points.
Make sure your attendance is recorded on Moodle ​before you leave recitation​.