14
votes
Accepted
Solution to Codejam 2019 1A (Pylons) in C
These coding competition sites are great at teaching you tricks and algorithms, but they are terrible at teaching you to write readable and maintainable code. Let's see how we can improve the latter.
...
- 40.6k
9
votes
Multiperson chat server using the select() API
log.h
I don't think that calling code has any need for TS_BUF_LENGHT, so this could be moved to the implementation file. ...
- 65.4k
8
votes
Rock, Paper, Scissors game with CPU
int games_number = 0, games_played = 0, user_wins = 0, computer_wins = 0, even_games = 0; //Counters
Wow, that's a lot of counters!
When choosing a data ...
- 7,031
8
votes
Event functionality in C
Files
The EventListener.h file should contain only declarations, as it needs to be safe to include in object files that are linked together. Put the definitions ...
- 65.4k
7
votes
Multiperson chat server using the select() API
Answers to your questions
Is my code POSIX compliant?
That question doesn't make sense. Your code does not implement the POSIX specification, so there is no question about compliance. You might use ...
- 40.6k
6
votes
C program for storing the time of the sunset and sunrise
General Observations
Does my code meet C99 standards?
Not exactly, it meets an earlier standard than C99, since C99 is generally backwards compatible with the earlier standards it compiles just fine ...
- 20.8k
6
votes
Rock, Paper, Scissors game with CPU
Many points already covered.
Check input functions return values
...
- 26.6k
6
votes
Accepted
Write a function reverse(s) that reverses the character string s. Use it to write a program that reverses its input a line at a time
Your implementation is not what the exercise asked for. It asked for a function that reverses a string (implied: in-place), and separately, I/O to read and print lines using that function. What it did ...
- 55.3k
6
votes
Follow-up: C program for storing the time of the sunset and sunrise
General Observations
I was hoping you would do a follow up question.
This is definitely an improvement, I can see more issues I should comment on, which was harder to do in the first version.
I ...
- 20.8k
6
votes
Accepted
Write a program entab that replaces strings of blanks by the minimum number of tabs and blanks to achieve the same spacing
Thank you for putting your work out there, it's brave of you!
That is how we improve.
The motivation for CHARMAX / LINEMAX is unclear,
given that they are not part of the problem specification.
Gold ...
- 7,031
5
votes
Follow up: A chat server using the select() API
Nice effort.
This review only addresses 2 of the 10 questions. I hope OP gets a review of the other 8 questions too.
Does any part of my code exhibit undefined behaviour?
Calls to ...
- 26.6k
4
votes
Write a function reverse(s) that reverses the character string s. Use it to write a program that reverses its input a line at a time
Independent of whether the function reverseString as written is doing what it should, it has an off-by-one error. In the loop ...
- 41
4
votes
Write a function reverse(s) that reverses the character string s. Use it to write a program that reverses its input a line at a time
The main program can be simplified by using a function you probably haven't read about yet called fgets. This function reads a line of text at a time. The variable <...
- 20.8k
4
votes
Rock, Paper, Scissors game with CPU
When it comes to code structure, here are some tips that may be helpful:
Don't use gotos when you can achieve the same behaviour with ...
- 41
4
votes
Accepted
Rock, Paper, Scissors game with CPU
move the srand to the top, no reason to call it multiple times
Get rid of the goto and instead rely an outer ...
- 589
4
votes
Accepted
Finding the sum of 2^x and all powers of 8 less than 2^x
c should not exist, and calculating n before your p%3 check is not a good idea. Further, don'...
- 55.3k
4
votes
Accepted
Compute lp-norm of a vector in parallel with MPI
Your assignment is ambiguous. You can indeed create the vector on one process and broadcast it, but that is bad MPI practice for two reasons: it's a sequential bottleneck, and it means that process ...
- 459
4
votes
Simple photomosaic generator
static const char *cache_filename = "/home/wilson/.cache/photomosaics/avgs";
Recommend you define a helper function which
returns the ...
- 7,031
4
votes
Parse program arguments of the form key=value
I certainly prefer variant A. Despite the extra function call, it's much easier to use correctly. Consider for example that some maintainer (perhaps you) needs to change the name of one of the ...
- 65.4k
4
votes
Accepted
Write a Program Detab That Replaces Tabs in the Input with the Proper Number of Blanks to Space to the Next Tab Stop
Overall: Aside from bug, a very good post.
Nice layout & formatting
Good object names
Bug: Inconsistent size
With char line[BUFSIZ]; and C definition of "...
- 26.6k
4
votes
C program for storing the time of the sunset and sunrise
Overall
Ambitious and good effort.
Enable all compiler warnings.
Use double instead of float.
Make use of C standard library ...
- 26.6k
4
votes
Follow-up: C program for storing the time of the sunset and sunrise
Are there major issues with my code?
Reconsider astronomical calculations and local time functions: Keep them separate. For astronomy, use double with a ...
- 26.6k
4
votes
Wipe a directory tree
The code is very dense, to the extent that it harms readability. I'm not a fan of variable names such as B, especially for globals. We could do with better layout ...
- 65.4k
4
votes
Accepted
Event functionality in C
In addition to Toby's comments, here are two more issues that should be looked into.
trigger needs to be volatile
The trigger variable in your EventListener struct ...
- 266
4
votes
Accepted
Follow up: A chat server using the select() API
Answers to the remaining 8 questions
Could any of these syscalls block?
That's an excellent question to ask for a program like this. There are lots of system calls in your code that can block, apart ...
- 40.6k
3
votes
C program for storing the time of the sunset and sunrise
Let's look closely at calc_sun_time(). The first thing that strikes me is that it returns a float, but there's nothing to ...
- 65.4k
3
votes
C program for storing the time of the sunset and sunrise
(This answers tries to address good practices, but doesn't consider the question of "standard c". This answer is also specific to POSIX)
Standard constants
Use ...
- 340
3
votes
Parse program arguments of the form key=value
As with many things in C, the answer is "use a macro."
Hard-coding values is error-prone because there is the risk you will either (a) get a value wrong; (b) change one of the values but not ...
- 12.2k
3
votes
Follow-up about computing lp norm with MPI
Allocate to the referenced object, not type
Code obliges a reviewer to type check vec, which is defined someplace else.
It is easier to code right, review and ...
- 26.6k
3
votes
Follow-up about computing lp norm with MPI
This code looks good. In particular I like how you handled the rem elements. There is a yet more elegant scheme: define ...
- 459
Only top scored, non community-wiki answers of a minimum length are eligible