CS 201 Homework Assignment 3

CS 201
Homework Assignment 3

In this homework, you will implement a simple movie rental system using linked lists. The movie
rental system will consist of a collection of movies and a collection of subscribers. The subscribers will
be able to rent movies and will be able to return the movies to the movie rental system as described
below. The system will store all rental transactions. Each transaction will contain the subscriber id and
the id of the movie that the subscriber rented, and whether or not this movie is returned to the rental
system.
In your implementation, you MUST keep the subscribers in a sorted linked list where the subscribers
are stored as sorted according to their subscriber ids and MUST keep the movies in a sorted linked list
where the movies are stored as sorted according to their movie ids. Also, for each of these subscribers,
you MUST use another sorted linked list to store their transactions where the transactions are stored
as sorted according to their movie ids. All lists are expected to be linear singly linked lists.
The movie rental system will have the following functionalities. The details of these functionalities
are given below:
1. Load movies and subscribers from input files
2. Remove a movie
3. Add a movie
4. Remove a subscriber
5. Rent a movie by a subscriber
6. Return a movie by a subscriber
7. Show the list of all movies rented by a subscriber
8. Show the list of all subscribers who have rented a particular movie
9. Show the list of all movies
10. Show the list of all subscribers
Load movies and subscribers from input files: The movie rental system will load the collection
of movies and the list of subscribers from the given two input files given at its declaration: one for the
collection of movies and the other one for the list of subscribers. Therefore, you will write a constructor
for the MovieRentalSystem class below. This constructor will take the names of the input files as
parameters, read the contents of the files, and store the movie and subscriber information in linked lists.
If at least one of these input files does not exists, your system should give a warning message.
Each movie will have a movie id and can have multiple copies. The input file containing movie
information will include the number of movies in the first line of the file, and will have one line per movie
in the rest of the file. For the sake of simplicity, after the first line, each line will contain a movie id and
the number of copies of that movie. You may assume that the movie ids are unique positive integers and
the number of copies for each movie is a positive integer.
Each subscriber will have a subscriber id. The input file containing subscriber information will consist
of the number of subscribers in the first line of the file, and will have one line per subscriber in the rest
of the file. After the first line, each line will contain a subscriber id. You may assume that the subscriber
ids are unique positive integers.
Remove a movie: The movie rental system will allow to remove an existing movie specified with
its movie id. If the movie does not exist (i.e., if there is no movie with the specified id), the system
should display a warning message. This operation cannot remove the movie at least one copy of which
has currently been rented by a subscriber but has not been returned. In this case, it should display a
message.
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Add a movie: The movie rental system will allow to add a new movie specified with its movie id.
If the movie already exists (i.e., if there is a movie with the specified id), the system should display a
warning message. Otherwise the system should add the movie sorted by id.
Remove a subscriber: The movie rental system will allow to remove an existing subscriber specified
with its subscriber id. If the subscriber does not exist (i.e., if there is no subscriber with the specified
id), the system should display a warning message. This operation will remove all of the transactions for
this subscriber if all of the movies rented by this subscriber have been returned. If there is at least one
movie which has currently been rented by the subscriber but has not been returned, the system will not
allow this operation and should display a message.
Rent a movie by a subscriber: The movie rental system will allow to rent a particular movie by a
particular subscriber. For this operation, the movie id and the subscriber id have to be specified. The
system should first check whether or not this movie exists; if it does not, it should not allow the operation
and display a warning message. The system should also check whether or not this subscriber exists; if
he/she does not, it should not allow the operation and display a warning message. If both the movie
and the subscriber exist and the movie has a copy available for renting, the renting operation must be
performed. If both the movie and the subscriber exist but the movie does not have a copy available for
renting, a warning message should be displayed. Note that a subscriber can rent multiple movies and
multiple copies of the same movie if available.
Return a movie by a subscriber: The movie rental system will allow a subscriber to return a movie.
For this operation, the subscriber id and the movie id have to be specified. If there is no transaction
corresponding to the given subscriber id and movie id, the system will display a warning message. Note
that a transaction is characterized with subscriber id and movie id. Thus, both of these must be matched.
If they all match, the system will record that the rental transaction has been completed and that movie
can now be rented by other subscribers. The system should store all transaction history and should not
remove any transaction information. However, in order to understand that the movie has been returned,
it should modify the corresponding transaction accordingly. For example, if a movie was rented by a
subscriber and was already returned, a new request for returning the movie should result in a warning
message.
Show the list of all movies rented by a subscriber: The movie rental system will allow to display
the list of all movies that were rented by a subscriber id. This list includes, for each movie, the movie id
and whether it was returned or not. Note that this operation displays all movies – those were rented and
returned as well as those were rented but not returned. If the subscriber has not rented any movie, the
system should display a warning message. If the subscriber does not exist (i.e., if there is no subscriber
with the specified id), the system should display a warning message.
Show the list of all subscribers who have rented a particular movie: The movie rental system
will allow to display the list of all subscribers that rented a particular movie. This list includes, for
each subscriber, the subscriber id and whether the movie was returned or not. If no one has rented that
particular movie, the system displays a warning message. If the movie does not exist (i.e., if there is no
movie with the specified id), the system should display a warning message.
Show the list of all movies: The movie rental system will allow to display a list of all movies. The
list includes the movie id and the number of copies for these movies.
Show the list of all subscribers: The movie rental system will allow to display a list of all subscribers.
The list only includes the subscriber id for these subscribers.
Below is the required public part of the MovieRentalSystem class that you must write in this assignment. The name of the class must be MovieRentalSystem, and must include these public member
functions. We will use these functions to test your code. The interface for the class must be written in a file named MovieRentalSystem.h and its implementation must be written in a file named
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MovieRentalSystem.cpp. You can define additional public and private member functions and data
members in this class. You can also define additional classes in your solution.
class MovieRentalSystem {
public:
MovieRentalSystem( const string movieInfoFileName,
const string subscriberInfoFileName );
~MovieRentalSystem();
void removeMovie( const int movieId );
void addMovie( const int movieId, const int numCopies );
void removeSubscriber( const int subscriberId );
void rentMovie( const int subscriberId, const int movieId );
void returnMovie( const int subscriberId, const int movieId );
void showMoviesRentedBy( const int subscriberId ) const;
void showSubscribersWhoRentedMovie( const int movieId ) const;
void showAllMovies() const;
void showAllSubscribers() const;
};
Here is an example test program that uses this class and the corresponding output. We will use
a similar (but different) program to test your solution so make sure that the name of the class is
MovieRentalSystem, its interface is in the file named MovieRentalSystem.h, and the required functions
are defined as shown above. Since we also test your solution with different programs, you should make
sure that your solution will work for other programs (main functions) as well. Thus, test your solution
with your own driver program. You can assume that the movie ids and subscriber ids are entered as
positive integers.
Example test code:
#include <iostream>
#include "MovieRentalSystem.h"
using namespace std;
int main( ) {
MovieRentalSystem firstMRS( "my_movies.txt", "subscribers.txt" );
cout << endl;
MovieRentalSystem MRS( "movies.txt", "subscribers.txt" );
cout << endl;
MRS.showAllMovies();
cout << endl;
MRS.showAllSubscribers();
cout << endl;
MRS.removeMovie( 600 );
MRS.removeMovie( 600 );
MRS.removeMovie( 70 );
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cout << endl;
MRS.addMovie( 99, 3 );
cout << endl;
MRS.showAllMovies();
cout << endl;
MRS.rentMovie( 1111, 10 );
MRS.rentMovie( 1111, 20 );
MRS.rentMovie( 7777, 10 );
MRS.rentMovie( 6666, 10 );
MRS.rentMovie( 7777, 80 );
MRS.rentMovie( 6666, 100 );
MRS.rentMovie( 4444, 40 );
MRS.rentMovie( 4444, 50 );
MRS.rentMovie( 1234, 30 );
MRS.rentMovie( 1111, 33 );
MRS.rentMovie( 1234, 33 );
cout << endl;
MRS.returnMovie( 7777, 80 );
MRS.returnMovie( 6666, 100 );
MRS.returnMovie( 1111, 20 );
MRS.returnMovie( 4444, 10 );
MRS.returnMovie( 1111, 20 );
cout << endl;
MRS.rentMovie( 3333, 80 );
MRS.rentMovie( 8888, 100 );
MRS.rentMovie( 1111, 100 );
MRS.rentMovie( 1111, 100 );
cout << endl;
MRS.rentMovie( 1111, 20 );
MRS.returnMovie( 1111, 20 );
MRS.rentMovie( 1111, 20 );
cout << endl;
MRS.showMoviesRentedBy( 1111 );
MRS.showMoviesRentedBy( 8888 );
MRS.showMoviesRentedBy( 2222 );
MRS.showMoviesRentedBy( 1234 );
cout << endl;
MRS.showSubscribersWhoRentedMovie( 10 );
MRS.showSubscribersWhoRentedMovie( 100 );
MRS.showSubscribersWhoRentedMovie( 30 );
MRS.showSubscribersWhoRentedMovie( 70 );
cout << endl;
MRS.removeMovie( 100 );
cout << endl;
MRS.removeSubscriber( 1111 );
cout << endl;
MRS.removeSubscriber( 5555 );
cout << endl;
MRS.removeSubscriber( 6666 );
cout << endl;
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MRS.showAllSubscribers();
cout << endl;
MRS.showAllMovies();
cout << endl;
return 0;
}
The input file “subscribers.txt” has the following content:
9
8888
3333
6666
1111
2222
9999
5555
4444
7777
The input file “movies.txt” has the following content:
15
100 3
400 1
90 1
10 2
30 1
600 1
40 2
60 3
50 6
70 2
500 1
80 1
20 1
200 1
300 3
Output of the example test code:
Input file my_movies.txt does not exist
9 subscribers and 15 movies have been loaded
Movies in the movie rental system:
10 2
20 1
30 1
40 2
50 6
60 3
5
70 2
80 1
90 1
100 3
200 1
300 3
400 1
500 1
600 1
Subscribers in the movie rental system:
1111
2222
3333
4444
5555
6666
7777
8888
9999
Movie 600 has been removed
Movie 600 does not exist
Movie 70 has been removed
Movie 99 has been added
Movies in the movie rental system:
10 2
20 1
30 1
40 2
50 6
60 3
80 1
90 1
99 3
100 3
200 1
300 3
400 1
500 1
Movie 10 has been rented by subscriber 1111
Movie 20 has been rented by subscriber 1111
Movie 10 has been rented by subscriber 7777
Movie 10 has no available copy for renting
Movie 80 has been rented by subscriber 7777
Movie 100 has been rented by subscriber 6666
Movie 40 has been rented by subscriber 4444
Movie 50 has been rented by subscriber 4444
Subscriber 1234 does not exist
Movie 33 does not exist
Subscriber 1234 and movie 33 do not exist
Movie 80 has been returned by subscriber 7777
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Movie 100 has been returned by subscriber 6666
Movie 20 has been returned by subscriber 1111
No rental transaction for subscriber 4444 and movie 10
No rental transaction for subscriber 1111 and movie 20
Movie 80 has been rented by subscriber 3333
Movie 100 has been rented by subscriber 8888
Movie 100 has been rented by subscriber 1111
Movie 100 has been rented by subscriber 1111
Movie 20 has been rented by subscriber 1111
Movie 20 has been returned by subscriber 1111
Movie 20 has been rented by subscriber 1111
Subscriber 1111 has rented the following movies:
10 not returned
20 returned
20 returned
20 not returned
100 not returned
100 not returned
Subscriber 8888 has rented the following movies:
100 not returned
Subscriber 2222 has not rented any movies
Subscriber 1234 does not exist
Movie 10 has been rented by the following subscribers:
1111 not returned
7777 not returned
Movie 100 has been rented by the following subscribers:
1111 not returned
1111 not returned
6666 returned
8888 not returned
Movie 30 has not been rented by any subscriber
Movie 70 does not exist
Movie 100 cannot be removed -- at least one copy has not been returned
Subscriber 1111 cannot be removed -- at least one movie has not been returned
Subscriber 5555 has been removed
Subscriber 6666 has been removed
Subscribers in the movie rental system:
1111
2222
3333
4444
7777
8888
9999
Movies in the movie rental system:
10 2
20 1
7
30 1
40 2
50 6
60 3
80 1
90 1
99 3
100 3
200 1
300 3
400 1
500 1
IMPORTANT NOTES:
Do not start your homework before reading these notes!!!
NOTES ABOUT IMPLEMENTATION:
1. You ARE NOT ALLOWED to modify the given parts of the header file. You MUST use linked
lists in your implementation. You will get no points if you use dynamic or fixed-sized arrays or
any other data structures such as vectors/arrays from the standard library. However, if necessary,
you may define additional data members and member functions. You may also define additional
classes.
2. Moreover, you ARE NOT ALLOWED to use any global variables or any global functions.
3. Output message for each operation MUST match the format shown in the output of the example
code.
4. Your code MUST use linked lists to store movie, subscriber, and transaction data in your implementations. You must use your own implementations of linked lists. You can adapt the codes and
pseudocodes in the Carrano book. However, you are NOT allowed to use any existing codes from
other sources (including the codes given in other textbooks, found on the internet, and belonging
to your classmates, etc.). Furthermore, you are NOT allowed to use any data structure or related
function from the C++ standard template library (STL).
5. Your code MUST NOT have any memory leaks. You will lose points if you have memory leaks in
your program even though the outputs of the operations are correct. To detect memory leaks, you
may want to use Valgrind which is available at http://valgrind.org.
6. Otherwise stated in the description, you may assume that the inputs for the functions are always
valid (e.g., number of copies of a movie is a valid positive integer number) so that you do not need
to make any input checks.
NOTES ABOUT SUBMISSION:
1. In this assignment, you must have separate interface and implementation files (i.e., separate .h and
.cpp files) for your class. We will test your implementation by writing our own driver .cpp file which
will include your header file. For this reason, your class’ name MUST BE “MovieRentalSystem”
and your files’ name MUST BE “MovieRentalSystem.h” and “MovieRentalSystem.cpp”. You
should submit these two files (and any additional files if you wrote additional classes in your
solution) as a single archive file (.zip file).
2. The code (main function) given above is just an example. We will test your implementation using
different scenarios, which will contain different function calls. Thus, do not test your implementation only by using this example code. We recommend you to write your own driver files to make
extra tests. However, you MUST NOT submit these test codes (we will use our own test code). In
other words, do not submit a file that contains a function named main.
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3. You should put all of your .h and .cpp files into a folder and zip the folder (in this zip file, there
should not be any file containing a main function). The name of this zip file should conform to
the following name convention: secX-Firstname-Lastname-StudentID.zip where X is your section
number. The submissions that do not obey these rules will not be graded.
4. Make sure that each file that you submit (each and every file in the archive) contains your name,
section, and student number at the top as comments.
5. You are free to write your programs in any environment (you may use Linux, Windows, MacOS,
etc.). On the other hand, we will test your programs on “dijkstra.ug.bcc.bilkent.edu.tr” and we
will expect your programs to compile and run on the dijkstra machine. If we could not get your
program properly work on the dijkstra machine, you would lose a considerable amount of points.
Thus, we recommend you to make sure that your program compiles and properly works on dijkstra.ug.bcc.bilkent.edu.tr before submitting your assignment.
6. This assignment is due by 23:59 on Sunday, December 11, 2022. You should upload your work to
Moodle before the deadline. No hardcopy submission is needed. The standard rules about late
homework submissions apply. Please see the course home page for further discussion of the late
homework policy.
7. We use an automated tool as well as manual inspection to check your submissions against plagiarism. Please see the course home page for further discussion of academic integrity and the honor
code for programming courses in our department.
8. This homework will be graded by your TA Mahmud Sami Aydın (sami.aydin at bilkent.edu.tr).
Thus, you may ask your homework related questions directly to him. There will also be a forum
on Moodle for questions.
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