The purpose of this assignment is to do more involved work with pointers, linked lists, and memory allocation, to do a little work with command line arguments and reading from a file, and to learn to free all allocated memory.
1. Your C code should adhere to the coding standards for this class as listed in the Documents section on the Resources tab for Piazza. This includes protecting against buffer overflows whenever you read strings.
2. Your programs should indicate if they executed without any problems via their exit status, i.e., the value returned by the program when it terminates:
Execution Exit Status
Normal, no problems 0
Error or problem encountered 1
3. Under bash you can check the exit status of a command or program cmd by typing the command “echo $?” immediately after the execution of cmd. A program can exit with status n by executing “exit(n)” anywhere in the program, or by having main() execute the statement “return(n)”.
4. Remember your code will be graded on lectura using a grading script. You should test your code on lectura using the diff command to compare your output to that of the example executable.
5. To get full points your code should compile without warnings or errors when the -Wall flag is set in gcc
6. Anytime you input a string you must protect against a buffer overflow. Review slides 69 – 74 of the basic_C deck.
7. You must check the return values to system calls that might fail due to not being able to allocate memory. (e.g. Check that malloc/calloc don’t return NULL) getline() is an exception to this rule.
8. Your code must run without errors using valgrind.
9. NEW REQUIREMENT, your program must free all allocated memory before exiting.
Example executables of the programs will be made available. You should copy and run these programs on lectura to test your program’s output and to answer questions you might have about how the program is supposed to operate. Our class has a home directory on lectura which is:
You all have access to this directory. The example programs will always be in the appropriate assignments/assg#/prob# subdirectory of this directory. They will have the same name as the assigned program with “ex” added to the start and the capitalization changed to maintain camelback. So, for example, if the assigned program is theBigProgram, then the example executable will be named exTheBigProgram. You should use the appropriate UNIX commands to copy these executables to your own directory.
Your programs will be graded by a script. This will include a timeout for all test cases. There must be a timeout or programs that don’t terminate will cause the grading script to never finish. This time out will never be less than 10 times the time it takes the example executable to complete with that test input and will usually be much longer than that. If your program takes an exceedingly long time to complete compared to the example code, you may want to think about how to clean up your implementation.
You will be required to include a Makefile with each program. Running the command:
should create the executable file progName, where progName is the program name listed for the problem. The gcc command in your Makefile must include the -Wall flag. Other than that, the command may have any flags you desire.
Your solutions are to be turned in on the host lectura.cs.arizona.edu. Since the assignment will be graded by a script, it is important you have the directory structure and the names of the files exact. Remember that UNIX is case sensitive, so make sure the capitalization is also correct. For all our assignments the directory structure should be as follows: The root directory will be named assg#, where # is the number of the current assignment. Inside that directory should be a subdirectory for each problem. These directories will be named prob# where # is the number of the problem within the assignment. Inside these directories should be any files required by the problem descriptions. For this assignment the directory structure should look like:
assg8 prob1 calls.c Makefile
To submit your solutions, go to the directory containing your assg8 directory and use the following command:
turnin cs352f21-assg8 assg8