Description

This assignment was locked Sep 29 at 12:33am.
GOALS OVERVIEW SPECS HINTS REQUIREMENTS SUBMITTING

Learning GOALS
The purpose of this assignment is to practice writing C programs and gain experience working in this low-level, non-object oriented language. After completing both parts A and B of this project, you should be comfortable with pointers, arrays, address arithmetic, structures, command-line arguments, and file I/O in C. For this part, your focus will be on pointers, arrays and address arithmetic.
OVERVIEW
Tic-Tac-Toe is a game where two players alternate putting their mark (either X or O) on a game board until one player wins or there are no spaces available to mark (see Tic-Tac-Toe Wikipedia
(https://en.wikipedia.org/wiki/Tic-tac-toe) ). In a typical game of tic-tac-toe, the game board is a 3×3 grid and the winner is the first to get 3 of their marks “in a row” either horizontally, vertically, or diagonally. For this assignment, you’ll be completing the program n_in_a_row.c, which processes a file containing the current game state, represented as a 2D grid of Xs and Os. Your task is verify if the current state of the game board is valid or not.
The game board size will be generalized to use a grid of n rows and n columns. This will require you to work with a dynamically allocated 2D array (heap allocation). The first value in the input file will be the value of n, the board size. Note the total number of Xs plus Os on the board will be in the range of 0 to n*n.
You’re welcome to develop the solution in phases. You could first code a solution that uses indexing. Once you have that solution working, you can replace indexing with pointer arithmetic before final testing and submission. If you do this approach, make sure to replace all accesses to your board to use address arithmetic and dereferencing to avoid a penalty.
You’re strongly encouraged to use incremental development to code your solution rather than coding the entire solution followed by debugging that entire code. Incremental development adds code in small increments. After each increment is added, you test it to work as desired before adding the next increment of code. Bugs in your code are easier to find since they’re more likely to be in the new code increment rather than the code you’ve already tested.
SPECIFICATIONS
You are to develop your solution using the skeleton code in the file n_in_a_row.c found on the CS Linux computers at:

The program n_in_a_row.c is run as follows:

Where <input_filename> is the name of the file that contains the data representing the tic-tac-toe board.
The format of the file is as follows:

that corresponds to the following board with X and O marks:

Several sample input files, named board1.txt through board4.txt, are provided in the directory as shown in the example below:

These test files are meant to help you start testing your program. You’ll need to create your own board files to test your program fully. We’ll use secret test files to evaluate your program’s correctness.
We’ve already provided code in the skeleton that reads and parses the input file, which you’ll use to construct a dynamically allocated 2D array representing the board.
an odd size; even size boards are invalid either the same number Xs as Os, or 1 more X than O since we’re assuming X always moves first either no winner or one winner; X and O cannot both be winners either one winning line (i.e., row, column, or diagonal), or two winning lines that intersect on one mark; two parallel winning lines are invalid
The sample runs below shows the expected behavior of the program:

HINTS
Using library functions is something you will do a lot when writing programs in C. Each library function is fully specified in a manual page. The man command is very useful for learning the parameters a library function takes, its return value, detailed description, etc. For example, to view the manual page for fopen, you would issue the command man fopen. If you are having trouble using man, the same manual pages are also available online. You will need some of these library functions to write this program and will see that some of them are already used in our code. You do not need to use all of these functions since a couple of them are just different ways to do the same thing.
fopen() to open the file.
malloc() to allocate memory on the heap free() to free up any dynamically allocated memory fgets() to read each input from a file. fgets can be used to read input from the console as well, in which case the file is stdin, which does not need to be opened or closed. An issue you need to consider is the size of the buffer. Choose a buffer that is reasonably large enough for the input. fscanf()/scanf(): Instead of fgets() you can also use the fscanf()/scanf() to read input from a file or stdin. Since this allows you to read formatted input you might not need to use strtok() to parse the input. fclose() to close the file when done. printf() to display results to the screen. fprintf() to write output to a file.
atoi() to convert the input which is read in as a C string into an integer strtok() to tokenize a string on some delimiter character. In this program the input file for a square has every row represented as columns delimited by a comma. See here
(http://www.tutorialspoint.com/c_standard_library/c_function_strtok.htm) for an example on how to use strtok to tokenize a string.
REQUIREMENTS
Your program must dynamically allocate (i.e., on the heap) the tic-tac-toe board.
Your program must use address arithmetic and dereferencing to access the array representing the board.
Your program must operate exactly as the sample runs above.
Your program must print an error message, as shown in the sample runs above, and then call exit(1) if the user invokes the program incorrectly (for example, without any arguments, or with two or more arguments).
Your program must check the return values for errors of the library functions, malloc(), fopen(), and fclose(). Handle errors by displaying an appropriate error message and then calling exit(1).
Your program must properly free up all dynamically allocated memory at the end of the program.
Your program must follow style guidelines as given in the Style Guide.
Your program must follow commenting guidelines as given in the Commenting Guide.
We will compile your programs with gcc -Wall -m32 -std=gnu99 on the Linux lab machines. So, your programs must compile there, and without warnings or errors.
SUBMITTING & VERIFYING
SUBMISSION FOR p2A HAS BEEN ENABLED.
1.) Submit only the file listed below under Project p2A in Assignments on Canvas. Do not zip, compress, or submit your file in a folder.
n_in_a_row.c
2.) Verify your submission to ensure it is complete and correct. If not, resubmit all of your work rather than updating just some of the files.
Make sure you have submitted all the files listed above. Forgetting to submit or not submitting one or more of the listed files will result in you losing credit for the assignment.
Make sure the files that you have submitted have the correct contents. Submitting the wrong version of your files, empty files, skeleton files, executable files, corrupted files, or other wrong files will result in you losing credit for the assignment.
Make sure your file names exactly match those listed above. If you resubmit your work, Canvas will modify your file names as mentioned in Repeated Submission above. These Canvas modified names are accepted for grading.

Project p2A
Criteria Ratings Pts
1. Compiles without warnings or errors 6.0 pts
No warnings or errors 0.0 pts
One or more errors or at least 5 warnings 6.0 pts
2. Follows commenting and style guidelines 6.0 to >0.0 pts
Followed 0.0 pts
Not followed 6.0 pts
3. Implements CLA checking 3.0 pts
Meets specifications 2.0 pts
Minor problem
Error message does not match specification 1.0 pts
Major problem
Incorrect argc check, no error message displayed, or does not exit 0.0 pts
Does not check CLAs 3.0 pts
4. Checks return values of malloc() and fopen() 6.0 pts
Checks all 3.0 pts Checks some 0.0 pts Checks none 6.0 pts
5. Closes all opened
files – fclose() 3.0 pts Closed 2.0 pts Some closed 0.0 pts None closed 3.0 pts
Execution test: frees heap memory 6.0 pts
Freed 6.0 to >0 pts
Not all freed 6.0 pts
Execution test:
board1.txt (provided) 2.0 pts
Correct result 0.0 pts
Incorrect result 2.0 pts
Execution test:
board2.txt (provided) 2.0 pts
Correct result 0.0 pts
Incorrect result 2.0 pts
Execution test:
board3.txt (provided) 2.0 pts
Correct result 0.0 pts
Incorrect result 2.0 pts
Execution test:
board4.txt (provided) 2.0 pts
Correct result 0.0 pts
Incorrect result 2.0 pts

Criteria R atings Pts
Execution test:
valid1.txt (tie, complete board) 2.0 pts
Displays valid 0.0 pts
Incorrect result 2.0 pts
Execution test: valid2.txt (tie,
incomplete board) 2.0 pts
Displays valid 0.0 pts
Incorrect result 2.0 pts
Execution test:
valid3.txt (X wins, row + column) 2.0 pts
Displays valid 0.0 pts
Incorrect result 2.0 pts
Execution test:
valid4.txt (O wins,
column) 2.0 pts
Displays valid 0.0 pts
Incorrect result 2.0 pts
Execution test:
valid5.txt (X wins, row + diagonal) 1.0 pts
Displays valid 0.0 pts
Incorrect result 1.0 pts
Execution test:
valid6.txt (O wins, column + diagonal) 1.0 pts
Displays valid 0.0 pts
Incorrect result 1.0 pts
Execution test:
valid7.txt (O wins, two diagonals) 1.0 pts
Displays valid 0.0 pts
Incorrect result 1.0 pts
Execution test:
valid8.txt (X wins, row) 1.0 pts
Displays valid 0.0 pts
Incorrect result 1.0 pts
Execution test:
invalid1.txt (even board size) 1.0 pts
Displays invalid 0.0 pts
Incorrect result 1.0 pts
Execution test:
invalid2.txt (|X| > |O| +
1) 2.0 pts
Displays invalid 0.0 pts
Incorrect result 2.0 pts
Execution test:
invalid3.txt (|O| > |X|) 2.0 pts
Displays invalid 0.0 pts
Incorrect result 2.0 pts

Criteria Ratings Pts
Execution test: invalid4.txt (two X winning rows) 1.0 pts
Displays invalid 0.0 pts
Incorrect result 1.0 pts
Execution test: invalid5.txt (two O winning rows) 1.0 pts
Displays invalid 0.0 pts
Incorrect result 1.0 pts
Execution test: invalid6.txt (two X winning columns) 1.0 pts
Displays invalid 0.0 pts
Incorrect result 1.0 pts
Execution test: invalid7.txt (X and O winning columns) 2.0 pts
Displays invalid 0.0 pts
Incorrect result 2.0 pts
Total Points: 60.0