This README is still incomplete!
Homework 3 — Completing a Simple Amazon Prime Video Recommendation System
In this assignment you will complete the implementation of a simple recommendation system called New York Recommender. Your program will mimic some behaviors of the Amazon Prime Video Recommendation System. Please read the entire handout before starting to code the assignment.
Learning Objectives
- Practice managing dynamic memory.
- Practice using two-dimensional arrays.
Note: in this README, we use the term two-dimensional array and the term matrix interchangeably, as in this assignment, we assume these two terms have the same meaning.
Background
Amazon Prime Video recommends movies and tv shows to prime users. Prime users on the prime video page will see things like this:
and this:
In this assignment, you will be completing a program which aims to implement these two features: recommending movies and recommending tv shows to users.
Specification
In this assignment we assume there are 500 users in total, and we index these users from 0 to 499.
We assume there are 110 movies in total, indexed from 0 to 109.
We assume there are 100 tv shows in total, indexed from 0 to 99.
The index and the name of all the movies and shows are hardcoded in the main.cpp, just so you do not need to parse more input files.
You are required to define a class named RecommendationSystem. The class definition goes to recommendation.h and the implementation of the class goes to recommendation.cpp, which is provided but is incomplete. Your class must have (at least) two member variables, one is named userMovieRatingsMatrix, the other is named userShowRatingsMatrix, both are two-dimensional int pointers, i.e., int**. Two member functions to your class are provided, and you can call but should not modify these two functions.
Input Files
Two input files are provided: movieRatings.txt and showRatings.txt. The two files have the same format. For example, the following is the first few lines of the movieRatings.txt:
(87,3) (11,1) (14,1) (31,4) (101,4) (21,2) (23,1) (3,4) (38,5) (100,2) (109,1) (80,4) (15,3) (71,5) (52,5) (67,2) (78,2) (69,3) (72,2) (93,4) (35,3) (102,4) (81,4) (107,4) (79,4) (58,1) (105,5) (90,2) (6,3) (9,3) (53,4) (59,2) (62,2) (94,2) (54,2) (85,3) (57,5) (5,4) (32,4) (39,2) (42,2)
(6,1) (61,2) (109,2) (87,4) (28,4) (38,5) (22,4) (11,2) (59,4) (68,3) (33,5) (71,3) (72,4) (15,4) (49,3) (94,1) (55,1)
(76,3) (33,1) (78,4) (65,4) (62,4) (73,5) (1,4) (105,2) (34,4) (18,4) (75,4) (99,4) (94,1) (83,3) (14,5) (85,2) (26,4) (15,4) (21,4) (69,1) (10,4) (81,1) (22,3) (61,2) (7,2) (25,2) (43,4) (70,2) (6,5) (0,2) (38,4) (95,5) (107,4) (72,4) (49,2) (90,2) (2,4) (88,3) (104,2) (23,3) (97,5) (56,4) (58,4) (57,5) (100,1) (37,4) (80,4) (96,4) (42,4) (77,5) (3,1) (46,1) (29,3) (19,5) (103,5)
(26,4) (57,4) (84,5) (60,4) (70,2) (99,3) (87,5) (94,1) (81,4) (16,2) (67,2) (36,2) (103,4) (28,1) (97,4) (73,5) (45,1) (37,4) (13,2) (17,4) (11,5) (66,2) (10,4) (85,1) (51,5) (96,4) (4,4) (21,5) (9,2) (74,5) (50,3) (104,3) (15,2) (35,5) (101,1) (102,4) (77,5) (62,1) (34,4) (71,5) (20,5) (46,1) (44,1) (90,1) (49,1) (2,4) (80,3) (95,1) (24,5) (98,3) (8,3) (14,3) (47,1) (32,3) (29,1) (18,4) (63,4) (40,3) (59,2) (69,5) (100,1) (107,3) (55,4) (0,4)
(69,4) (63,2) (32,5) (31,4) (74,2) (46,1) (99,4) (26,4) (90,4) (89,1) (58,1) (27,5) (29,2) (7,4) (65,3) (60,5) (23,1) (97,4) (53,4) (39,5) (87,5) (47,3) (8,4) (15,1) (102,3) (35,4) (106,4) (73,5) (98,4) (42,4) (66,5) (76,1) (104,2) (94,1) (77,1) (56,4) (109,4) (54,4) (103,2) (71,2) (25,4) (92,5) (24,4) (52,4) (34,4) (14,3) (55,2) (22,4) (80,2) (44,2) (4,4) (75,3) (13,4) (91,4) (61,3) (82,1) (84,3) (28,2) (51,3) (30,4) (85,5) (62,4) (86,4) (70,4) (43,5) (33,4) (107,2) (64,5) (108,4) (9,3) (88,3) (11,1)
(10,4) (38,1) (0,4) (20,1) (41,3) (94,1) (64,5) (71,1) (22,4) (34,3) (96,1) (46,3) (50,5) (39,2) (109,4) (82,1) (65,5) (2,3) (37,4) (44,3) (69,1) (105,4) (30,4) (29,3)
(11,4) (98,2) (76,2) (50,2) (35,3) (16,1) (18,5) (70,4) (30,5) (3,2) (90,2) (36,1) (83,4) (102,2) (105,4) (49,4) (94,1) (85,2) (20,3) (107,1) (28,1) (48,2) (12,2) (15,4)
(67,3) (27,4) (58,2) (6,3) (42,5) (63,3) (0,5) (49,4) (53,4) (66,3) (17,2) (41,2) (90,1) (84,4) (83,4) (46,1) (22,4) (13,2) (15,1) (75,1) (11,4) (62,4) (102,4) (35,1) (5,5) (69,4) (81,3) (93,4) (44,1) (59,5) (31,4) (8,3) (47,5) (106,3) (7,1) (61,3) (51,3) (99,1) (54,1) (32,3) (78,4) (72,3) (24,1) (48,4) (40,4) (97,4) (74,2) (33,1) (26,3) (68,5) (95,4) (64,4) (4,3) (25,4) (103,3) (52,5) (65,5) (30,4) (28,2) (39,4) (18,2) (73,1) (105,3) (45,4) (38,2) (23,4) (16,2) (21,4) (2,4) (9,5) (77,2) (82,2) (19,3)
(82,1) (83,4) (64,1) (98,3) (94,2) (4,1) (38,5) (90,5) (31,1) (2,5) (61,1) (102,3) (103,1) (45,4) (89,4) (1,2) (85,4) (63,2) (49,4) (77,4) (28,1) (91,4) (8,4) (53,5) (46,4) (23,4) (73,2) (104,5) (62,4) (66,4) (25,2) (44,4) (9,1) (30,1) (29,1) (108,1) (48,1) (52,4) (76,1) (92,4) (15,3) (101,4) (59,1) (32,4) (22,2) (33,3) (21,2) (35,4) (65,2) (109,1) (69,5) (27,4)
(101,4) (37,2) (24,1) (0,4) (63,2) (71,5) (64,3) (2,4) (65,1) (45,4) (7,4) (50,2) (81,2) (93,1) (42,5) (83,4) (29,2) (21,2) (51,5) (86,4) (82,1) (108,2) (23,4) (40,2) (89,4) (88,3) (78,5) (107,4) (9,3) (56,5) (60,5) (46,5) (44,4) (67,3) (18,3) (10,4) (103,1) (8,5) (34,3) (12,5) (96,5) (35,2) (68,3) (61,1) (58,1) (20,3) (100,4) (97,4) (47,5) (95,1) (92,4) (32,5) (27,5) (52,4) (25,4) (5,4) (85,4) (57,2) (30,3) (76,4) (72,5) (1,5)
Each line is representing one user. Each user uses the Amazon star rating (as show in the following image) to rate a movie or a tv show (in the range of 1 to 5).
The first line of movieRatings.txt means, user 0 gives a rating of 3 to movie 87, gives a rating of 1 to movie 11, gives a rating of 1 to movie 14, gives a rating of 4 to moving 31, gives a rating of 4 to movie 101, gives a rating of 2 to movie 21, etc.
The second line of movieRatings.txt means, user 1 gives a rating of 1 to movie 6, gives a rating of 2 to movie 61, gives a rating of 2 to movie 109, gives a rating of 4 to moving 87, gives a rating of 4 to movie 28, gives a rating of 5 to movie 38, etc.
The 3rd line descirbes ratings given by user 2, the 4th line describes ratings given by user 3, etc.
The file showRatings.txt can be interpreted in the same way. It is just ratings in that file are for tv shows. In this assignment, your program should read these two input files and store the movie ratings in a matrix, and store the show ratings in another matrix.
Commands to Support & Program Output
Your program only needs to support one command:
nyrecommender.exe movieRatings.txt showRatings.txt output.txt userID numRecommendations
Here
- movieRatings.txt is the movie rating input file, already described above.
- showRatings.txt is the show rating input file, already described above.
- output.txt is where to print your output.
- userID specifies the ID of the user.
- numRecommendations specifies how many movies/shows your program will recommend to the user. For example, if numRecommendation is 5, then your program should try to print up to 5 movies and up to 5 tv shows.
When your program is executed, it produces up to numRecommendations recommended movies to the output file, and also produces up to numRecommendation recommended tv shows to the output file. Following is a sample output file:
Prime: Movies we think you'll like:
Elvis
The Shawshank Redemption
The Godfather
Schindler's List
Forrest Gump
Prime: TV shows we think you'll like:
Little Women
Game of Thrones
The Simpsons
Friends
The Crown
Note that these recommendations are specifically for this user - as specified by the command line argument userID. Apparently your program will produce different recommendations for different users.
- in the case where the number of command line argument is not 6, your program should use std::cerr to print the following message:
Usage: nyrecommender.exe movieRatings.txt showRatings.txt output.txt userID numRecommendations
Nothing should be printed to the output file in such a case.
- in the case where the userID command line argument is not in the range of 0-499, your program should use std::cerr to print the following error message:
Invalid User ID.
Nothing should be printed to the output file in such a case.
- in the case where the numRecommendations command line argument is 0, your program should produce the output file which contains the following message:
Prime: Movies we think you'll like:
Prime: TV shows we think you'll like:
Note: all the expected files contain an empty line at the very end, to match with that, you just need to make sure all your print statements end with std::endl; (or just endl; if you don't use std::).
Provided Code
Two cpp files are provided: main.cpp and recommendation.cpp. These two files are incomplete, and you should add your code into these two files. In addition, you should create the recommendation.h file, in which you define the RecommendationSystem class.
Existing Code in main.cpp
A helper function named process_one_line is provided in the main.cpp file. This function will help you to parse information from the input file, and update the matrix. This function takes three arguments, the first argument is a two-dimensional integer pointer, which is expected to point to the beginning memory location of a two-dimensional array, known as the matrix pointer. This function assumes the caller allocates and reclaims memory for matrix. The second argument is the index i, indicating which row of the matrix will be updated. The third argument is the string line, which represents one line of the input file.
void process_one_line(int** matrix, int i, std::string& line){
std::istringstream iss(line);
// process each (index, value) pair
int index, value;
char openParen, comma, closeParen;
// when used with integers, it reads characters until it encounters a non-digit character or whitespace. However, when used with characters, it reads a single character.
while (iss >> openParen >> index >> comma >> value >> closeParen) {
matrix[i][index] = value;
}
}
Let's take the first line of the movieRatings.txt as an example.
(87,3) (11,1) (14,1) (31,4) (101,4) (21,2) (23,1) (3,4) (38,5) (100,2) (109,1) (80,4) (15,3) (71,5) (52,5) (67,2) (78,2) (69,3) (72,2) (93,4) (35,3) (102,4) (81,4) (107,4) (79,4) (58,1) (105,5) (90,2) (6,3) (9,3) (53,4) (59,2) (62,2) (94,2) (54,2) (85,3) (57,5) (5,4) (32,4) (39,2) (42,2)
We know this first line represents movie ratings given by user 0. If this above line is stored in the line argument, passed to the process_one_line function, then this function will set:
- matrix[0][87] to 3 // it's the first row, and that corresponds to matrix[0], and we the rating to movie 87 is 3.
- matrix[0][11] to 1
- matrix[0][14] to 1
- matrix[0][31] to 4
- matrix[0][101] to 4
- matrix[0][21] to 2
- etc.
Let's present one more example, the following is the second line of the movieRatings.txt:
(6,1) (61,2) (109,2) (87,4) (28,4) (38,5) (22,4) (11,2) (59,4) (68,3) (33,5) (71,3) (72,4) (15,4) (49,3) (94,1) (55,1)
When feeding this line to the process_one_line function, it will set:
- matrix[1][6] to 1 // // it's the second row, and that corresponds to matrix[1], and the rating to movie 6 is 1.
- matrix[1][61] to 2
- matrix[1][109] to 2
- matrix[1][87] to 4
- matrix[1][28] to 4
- matrix[1][38] to 5
- etc.
In addition to this process_one_line function, the main.cpp also defines two global arrays, one array is named movies, which stores the index and the name of all the movies; the other array is named tvShows, which stores the index and the name of all the tv shows.
Existing Code in recommendation.cpp
Program Requirements & Submission Details
In this assignment, you are NOT allowed to use std::vector anywhere in your code. You must use dynamic memory to store the movie rating matrix, and the show rating matrix.
Use good coding style when you design and implement your program. Organize your program into functions: don’t put all the code in main! Be sure to read the Homework Policies as you put the finishing touches on your solution. Be sure to make up new test cases to fully debug your program and don’t forget to comment your code! Use the provided template README.txt file for notes you want the grader to read. You must do this assignment on your own, as described in the Collaboration Policy & Academic Integrity page. If you did discuss the problem or error messages, etc. with anyone, please list their names in your README.txt file.
Due Date: 02/08/2024, Thursday, 22:00pm.
Rubric
14 pts
- README.txt Completed (3 pts)
- One of name, collaborators, or hours not filled in. (-1)
- Two or more of name, collaborators, or hours not filled in. (-2)
- No reflection. (-1)
- OVERALL CLASS DECLARATION & IMPLEMENTATION AND CODING STYLE (Good class design, split into a .h and .cpp file. Functions > 1 line are in .cpp file. Organized class implementation and reasonable comments throughout. Correct use of const/const& and of class method const. ) (6 pts)
- No credit (significantly incomplete implementation) (-6)
- Putting almost everything in the main function. It's better to create separate functions for different tasks. (-2)
- Improper uses or omissions of const and reference. (-1)
- Function bodies containing more than one statement are placed in the .h file. (okay for templated classes) (-2)
- Functions are not well documented or are poorly commented, in either the .h or the .cpp file. (-1)
- Overly cramped, excessive whitespace, or poor indentation. (-1)
- Poor file organization: Puts more than one class in a file (okay for very small helper classes) (-1)
- Poor choice of variable names: non-descriptive names (e.g. 'vec', 'str', 'var'), single-letter variable names (except single loop counter), etc. (-2)
- Contains useless comments like commented-out code, terminal commands, or silly notes. (-1)
- DATA REPRESENTATION (Must use dynamic memory for the implementation.) (5 pts)
- No credit (significantly incomplete implementation). (-5)
- Does not define the RecommendationSystem class. (-5)
- Does not use dynamic memory to store the movie rating matrix. (-5)
- Does not use dynamic memory to store the show rating matrix. (-5)
- Uses std::vector anywhere in the code. (-5)
- Member variables are public. (-2)