CS101 Homework 4: Social Network

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1 CS101 Homework 4: Social Network Prof Tejada Program and report due: 11:59pm Wednesday, March 13 Design document due: 11:59pm Wednesday, March 6 1 Introduction For this assignment create user accounts for a social network to keep track of each user s information, such as year at USC, as well as a network of friends. The user account information is stored in a database file. The database file contains information about individual users. The network file contains information about which users are friends with each other. Friendship is a bi- directional relationship. This means that if user A is a friend of user B, then user B must also be a friend of user A. The database file must conform to the database file format specification. The default database filename is "db.txt" in the same directory as your program. The default network filename is network.txt. When your program starts, it must read the default database file and the network file to get all the information and store them in data structures. You must use a C++ record(struct) to represent a single user. You will need an array of users to hold the user database information. Create a 2 dimensional array of pointers to users, which will hold the friendship network between users. Your program will give the user the option to display all the user information in a table, including each user s friend connections. It will also allow you to alter the social network by adding/deleting users and adding/deleting friend connections.

2 2 What you will learn 1. Create your own C++ records and objects 2. Use File I/O to read/write text files containing structured data (records) 3. Use pointers and arrays 4. Understand the abstract representation of graphs (vertices/nodes=users, edges=friend connections) 3 Background Information and es Graph Representation: A graph is an abstract representation of the connections between objects. Each object (known as a node or vertex) is connected to others via edges. Visually, graphs are quite intuitive (see graph above). Here we see eight users (nodes or vertices) and the friend connections (edges) between them. Many interesting problems in computer science can be represented as graphs and algorithms defined to extract interesting information from the connections within the graph. For our purposes we will create a record to represent a single User which contains information about each user (name, etc.) and an two dimensional array of User pointers to represent the edge connections (friend relationships) for the user. e: In our system edges are undirected meaning friend connections are reflexive (i.e. if I m a friend with you, you are a friend with me). Other problems using graphs may require directed edges (i.e. non- reflexive relationships). Thus, when you add a friend connection from user1 to user2, be sure to add the connection from user2 to user1. The Database File Format: This program requires you to use File I/O techniques to read and write the user database from and to a file. Whenever we write a file containing structured data we need to define a file format (syntax) so we understand how to parse the file. We will represent all information as text and use the format specified below.

3 1: single number representing how many users are in the network 2: USC username 3: user first name 4: user last name 5: favorite TV show n-3: USC username n-2: user first name n-1: user last name n: favorite TV show An example db.txt file is shown below with 3 users. 3 stejada Professor Tejada Game of Thrones kshahabi TA Kaveh Supernatural jtanedo TA Jeff Doctor Who The Network File Format: We will represent all information as text and use the format specified below. 1: single number representing how many users are in the network 2: list of USC username for each friend of user1 separated by a space 3: list of USC username for each friend of user2 separated by a space 4: list of USC username for each friend of user3 separated by a space n-3: list of USC username for each friend of user n- 4 separated by a space n-2: list of USC username for each friend of user n- 3 separated by a space n-1: list of USC username for each friend of user n- 2 separated by a space n: list of USC username for each friend of user n- 1 separated by a space An example network.txt file is shown below with 3 users, where Professor Tejada is friends with both TA Kaveh and TA Jeff, but they are not friends with each other. 3 kshahabi jtanedo stejada stejada

4 The social network will be represented as a two dimensional array of User pointers. For example given the previous example db.txt and network.txt the network would be represented as a matrix: Username stejada kshahabi jtanedo stejada NULL Pointer to kshahabi Pointer to jtanedo kshahabi Pointer to stejada NULL NULL jtanedo Pointer to stejada NULL NULL 4 Design Document Write down electronically or on paper the answer to the following questions BEFORE beginning. You MUST do this BEFORE you begin to program or write code. Write a description of your algorithm. What are the individual steps? What are your functions? What are the input parameters of each function? What data needs to be maintained for each user? For all users? For the network of friends? What type of user input do you need? How will your program use this input to decide what statement to execute next? What data needs to be maintained for the total execution of your program (i.e. across several add/delete/display users)? What type? What kind of loops should then be used? What is your development plan? In what order will you implement and test your program? What is your development schedule? When will each stage of your program be completed? What is the algorithm and data structure you would create to represent your own study group of users in addition to and separate from the friend network? Blackboard submission (Due Wednesday March 6, 11:59pm) o Zip your Design Document and submit the zipped file to Blackboard. 5 Requirements Your program shall meet the following requirements for features and approach: 1. You may NOT use global variables. You instead need to pass appropriate arguments either by value or by reference. 2. Display a menu screen (several lines of text) of instructions (how to decode/encode). 3. Prompt the user to enter an action to perform. 4. Receive input from the user 5. Perform the action (add/delete/display user, add/delete friend connection, display friend s information) 6. Display status or results of action.

5 7. Use a record(struct) to represent a single user 8. Use an array of user records to hold all user database information 9. Create a two dimensional array of pointers to user for holding the friend connections. 10. Use functions in the program code implementation. 11. You must use well- formatted I/O (cout I/O manipulators) where appropriate. [If your program outputs messy looking output, points may be deducted.] 12. Use file I/O to read/write database file and network file 13. Allow the user to repeat the add/delete display process 14. Exit upon user choice where appropriate 6 Procedure 1. Define a record/struct to model a User. It should contain: a. A USC username b. A user first name c. A user last name d. A user s favorite TV show 2. Define a Database array of User. It should contain a list of at most 100 Users 3. Define a Network two dimensional array of User pointers. It should contain at most 100x100 friend connections. 4. Write a main program (social_network.cpp) that will create a Database of Users and then read Users data from a text file. It will create a Network array and then read the friend connections from a text file. The program should then loop through the progression of displaying a menu of options, accepting the user input, and processing the option. Your program should support the following operations: a. An add_user function to add a User to the database. b. A delete_user function to delete a User to the database. c. A display_user function to print out a User record to the screen d. A display_all function to print out all User record to the screen in a well formatted table.

6 e. A read_users function that initializes the User info from a file. f. A write_users function that writes the User info to a file g. An add_friend function given two usernames of users to add as friends h. A delete_friend function given two usernames of users to delete as friends i. A write_friends function that writes friend connections to a file. j. A read_friends function that reads friend connections from a file. k. A display_friends function given a username will print out all friends records to the screen in well formatted table. l. Any other function you need to manage the social network 5. Approach: To break this into pieces consider the following approach to build up your program: a. Create the User record/struct and an array of User to hold the database b. Create the network as a two dimensional array of pointers to User objects. c. Write a simple main program that implements the Menu system but with just the options to add users and print all users. d. Continue to add in functions incrementally to remove users, add friend connections, remove friend connections one at a time and implement that option in the menu system, testing each one individually before moving on to the next. e. Lastly, implement the File I/O capability to read in the database from a file or write it back out to a file. 6. Ensure all commands work and that you can write the updated database to a new database file and the updated friend connections to a new network file. Inspect the files to ensure its format and data are correct.

7 7 Report Include the following items in your report. Be sure to have your name and USC ID on the first page at the top. 1. Your answers from the design document (Due Wednesday March 6, 11:59pm) and also include a discussion of any design choices you made, any known errors, and any other information that will help us in grading your assignment. 2. A printout of 2 run- throughs of your program. 3. Place your social_network.cpp file and Report in a ZIPPED folder and submit that ZIP file. Failure to place the file in a ZIP file will lead to point deductions. Then submit the ZIP file via Blackboard. 4. Blackboard submission (Due Wednesday, March 13, 11:59pm) a. Zip your Report and your C++ program file together and submit the zipped file to Blackboard. Please also note that you must submit your code using the USC Blackboard System since the Blackboard System timestamps your submission. You should also verify what you have submitted is what you intended to submit. Please note that it is your responsibility to ensure that you have submitted valid submissions, meaning that your code must run on aludra, which is the machine that it will be graded on. 8 Late Policy All homework must be turned in on time. Late submissions will receive severe penalties. If you submit within 24 hours after the grace period, you will receive 80% of your grade. If you submit within 48 hours after the grace period, you will receive 50% of your grade. If you are unable to complete a homework assignment due to illness or family emergency, please see the instructor as soon as possible to get an extension. A doctor's note is required as proof of illness or emergency. In general, when you get sick, it's best to see a doctor and get a note just in case you may need it later.

8 Name: Score: / 100 Req. / Guideline Read Users from File and Display To Screen (Test 1) Adding Users and Writing to a File Add and Remove friend connections Wt. Score 10 (Excellent) 2 Reads in all User fields and friend connections correctly and displays them in well formatted table 2 Successfully able to add users at run- time and then write the updated database to a correctly formatted file. 2 Successfully add and remove friend connections and outputs to a network file. Error Cases 1 Database is not corrupted when invalid arguments are used Menu & Command Parsing Data Structures (record for user, array of pointers for friendships) 1 Menu prints correctly and parses commands correctly 1 Struct for user defined correctly and used correctly. Arrays of user objects and network of friends created Code Org. Well- organized 1 code (indented /readable) AND commented such that another person could easily follow what the code was attempting to accomplish as well as providing insight into your decisions Late TOTAL 8 (Good) 5 (Poor) 2 (Deficient) (0) Failure Reads in all User fields and friend connections correctly and displays them in an adequately formatted table Small error in the file format or database content. Friend connections are not reflexive (each user added to the other s friend list) Menu prints slightly improperly Acceptably organized code (indented /readable) AND commented in a reasonable manner to allow someone else to reasonably follow the code and provided some insight into your decisions 20% (1 Day Late) 50%(2 Days Late) Either misses a User while reading from the file or does not display a User or a field. Display format is adequate. Major error in the format or database contents. Add or removing friend connections corrupts other friend connections Database contents are corrupted when invalid arguments are used Menu prints incorrectly or command parsing requires extra steps (separate lines, etc.) Struct for user defined incorrectly and/or used incorrectly or arrays of users and user pointers not created Poorly organized code (indented/ readable) OR comments were disorganized and provided little insight into the code and implementation decisions. - 5 (Submission Instructions) Gross error in reading Users or display their info. Unable to write an updated database file. Gross errors when attempting to add or remove friend connections Database is completely corrupted/lost or program crashes on invalid arguments. Command parsing does not work. Struct or Arrays of pointers are defined but not used. Poorly organized code (indented/ readable) AND comments were disorganized or provided little insight into the code and implementation decisions. or does not compile Completely unorganized code and lacked helpful comments.