Activity for Lundin
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Comment | Post #279797 |
I went ahead and proposed a [move post between different categories feature request](https://meta.codidact.com/questions/279815). It would be generally handy to have, I think. (more) |
— | almost 4 years ago |
| Comment | Post #279797 |
Great idea. Although... is there a point in archiving old, finalized sandbox posts? Otherwise I believe that the best solution would make it possible for the poster move the post between categories, from sandbox to live challenges. (more) |
— | almost 4 years ago |
| Edit | Post #279722 |
Post edited: |
— | almost 4 years ago |
| Edit | Post #279814 |
Post edited: Got rid of break |
— | almost 4 years ago |
| Edit | Post #279814 | Initial revision | — | almost 4 years ago |
| Answer | — |
A: Prime Difference C (gcc), 126 129 bytes ```c N=9999;f(n){int p[N],i,j,P;memset(p,1,N);for(i=P=2;ii=n?j=N:(P=i);}e:return P;} ``` Try it online! This is an integer input/output function solution. The upper limit of prime number supported is the square root of`N`, so currently it counts prime numbers up to 9... (more) |
— | almost 4 years ago |
| Comment | Post #279755 |
However, chasing down a specific poorly-specified program output to a certain compiler, system + options could perhaps be an interesting and very different challenge. If you write a program that purposely does something bad, resulting in crazy results, then task people to find a system and compiler t... (more) |
— | almost 4 years ago |
| Comment | Post #279755 |
A problem with your example is that can only be reproduced with a non-standard compiler for that language. So you would have to specify to what extent non-standard language extensions are allowed and if your program relies on them... which in turn would be a major spoiler. Running `main;` on a confor... (more) |
— | almost 4 years ago |
| Comment | Post #279759 |
@Quintec That's a l (L). And yeah the reason that l and 1 look identical on some fonts is the reason why one shouldn't name identifiers like that. (more) |
— | almost 4 years ago |
| Comment | Post #279754 |
Isn't it a big problem that the robbers can just "brute force" it with trail & error by trying online compilers until they find a match? (more) |
— | almost 4 years ago |
| Comment | Post #279759 |
And yeah `(int){8<88}<<8` can be rewritten as `1<<8` or `u'\xff'+!!u'\xff'` as `u'\xff'+1` but I'm saving the 1 for a rainy day. (more) |
— | almost 4 years ago |
| Edit | Post #279759 | Initial revision | — | almost 4 years ago |
| Answer | — |
A: Output 256 in many different ways C, 8 solutions Standard C, no extensions. 1 solution snippet per line: ```c "llll"[3]^33^333 4444 5555-555-555-555-555-555-555-555-555-555-55-55-55-55-55-5-5-5-7-7 6666/26 (int){8<88}<<8 u'\xff'+!!u'\xff' 0XFFFFFeFF LINE ``` Somewhat naive solution so far, but the nu... (more) |
— | almost 4 years ago |
| Comment | Post #279743 |
If snippets are ok, what about necessary libs to make the snippet run? That is, to access some language features I would strictly speaking have to include/import etc a lib. (more) |
— | almost 4 years ago |
| Edit | Post #279722 | Initial revision | — | almost 4 years ago |
| Article | — |
Integer to Roman numeral The task is to take a decimal integer as input and print the corresponding Roman numeral with capital letters. The program must handle all positive integer numbers between 1 and 1000. Input can be assumed to be correct and no error handling is necessary. Example data: ``` Input Output 1 ... (more) |
— | almost 4 years ago |
| Comment | Post #279679 |
Oh, and `t` actually doesn't have to be char. So with gcc implicit int abuse, this should be possible: `t;f(char*s){s[1]?f(s+1):0;for(t=*s;s[1];*++s=t)*s=s[1];}`. (more) |
— | about 4 years ago |
| Comment | Post #279679 |
Also, switching `while` with `for` will save you lots. `for(char t=*s;s[1];*++s=t;)*s=s[1];` should work. So how about this? `f(char*s){s[1]?f(s+1):0;for(char t=*s;s[1];*++s=t)*s=s[1];}`, 59 bytes. (more) |
— | about 4 years ago |
| Comment | Post #279679 |
I think this might be a possible improvement: `f(char*s){s[1]?f(s+1):0;while(s[1]){char t=*s;*s=s[1];*++s=t;}}}`. In case s[1] is a character, it makes the recursive call and then while loop. If not, a `0;` dummy statement. `s[1]` is zero in that case so the while loop isn't executed. (more) |
— | about 4 years ago |
| Comment | Post #279657 |
`*p=b+strlen(gets(b))` works too but gives identical size. (more) |
— | about 4 years ago |
| Edit | Post #279657 |
Post edited: |
— | about 4 years ago |
| Edit | Post #279657 | Initial revision | — | about 4 years ago |
| Answer | — |
A: Reverse an ASCII string C (gcc), 62 bytes main(){char b[99],p=strchr(gets(b),0);for(;p-->b;)putch(p);} This relies on the usual gcc extension abuse. It assumes that max user input is 98 characters + null term, since this wasn't specified. EDIT: Revisited, function-based equivalent of the above (plus I have ... (more) |
— | about 4 years ago |
| Comment | Post #279639 |
Max length of input string? (more) |
— | about 4 years ago |
| Comment | Post #279635 |
Probably a good idea. If the OP makes an attempt to write the non-golfed version of the challenge, then they'll realize various requirements that need to be addressed. (more) |
— | about 4 years ago |
| Comment | Post #279601 |
What's the upper limit to number of items supported and the values themselves? Does it need to cover negative numbers? (more) |
— | about 4 years ago |
| Comment | Post #279426 |
How can you say that it relies on non-standard extensions while lecturing me about the standard at the same time? It's either, not both at once. (more) |
— | about 4 years ago |
| Comment | Post #279415 |
I think this is kind of cheating since that online compiler declares a main() elsewhere. Otherwise you could improve it to `m(){m();}`, 9 bytes, a recursive call that will eventually stack overflow with seg fault (more) |
— | about 4 years ago |
| Comment | Post #279383 |
Nice solution since it's quite straight-forward, +1. I managed 108 bytes with same compiler settings (default gcc) but a much more obscure solution [here](https://codegolf.codidact.com/a/279365/279534). (more) |
— | about 4 years ago |
| Answer | — |
A: 1, 2, Fizz, 4, Buzz! C (gcc), 108 bytes ```c h,i;main(){for(;i++<100;){char s[]="%dFizzBuzz ",b=i%5;h=s+2;printf(s+(i%3?b?h=32,0:6:b?h[1]=32,2:2),i);}} ``` Godbolt. Works on clang too. Contains some serious abuse of all that is holy: gcc extensions, misaligned writes, endianess, poorly-defined behavior... New... (more) |
— | about 4 years ago |
| Comment | Post #279479 |
Then maybe the Q&A category needs to be "seeded" with some example questions so that people understand what it's for. The current help for categories and FAQ on this site isn't helpful. (more) |
— | about 4 years ago |
| Comment | Post #279467 |
Seems to me like the majority of such questions should be asked on meta rather than Q&A. Otherwise this site has main site + 2 layers of meta... (more) |
— | about 4 years ago |
| Edit | Post #279466 | Initial revision | — | about 4 years ago |
| Answer | — |
A: What is the Q&A category for? I was thinking the same thing. Maybe instead there should be one category for code golf and leave the main Q&A is for other types of challenges and puzzles? (more) |
— | about 4 years ago |
| Comment | Post #279382 |
But essentially they are lying just to pose and feel good about themselves. If you post an ill-formed, non-conforming program in "language X", that also relies on non-standard extensions, you are actually not programming in language X but in something else. That gives them an unfair advantage to thos... (more) |
— | about 4 years ago |
| Comment | Post #279408 |
default-rules then? (more) |
— | about 4 years ago |
| Edit | Post #279461 |
Post edited: |
— | about 4 years ago |
| Edit | Post #279461 | Initial revision | — | about 4 years ago |
| Answer | — |
A: Bytes to Segfault C (compliant), 19 bytes (`gcc -std=c18 -pedantic-errors`) ```c int main(){main();} ``` Godbolt (more) |
— | about 4 years ago |
| Comment | Post #279408 |
This sounds reasonable enough, especially if help files can get kept up to date to match community consensus on meta. Maybe "code-golf-rules" or "challenge-rules" are better tag names though? Since standards might be confused with formal language standards. (more) |
— | about 4 years ago |
| Comment | Post #279426 |
Apart from using deprecated gcc extensions, this is non-conforming/ill-formed C++ with several constraint violations. (more) |
— | about 4 years ago |
| Comment | Post #279382 |
Again, "it generated a binary" is a horrible rationale, particularly in C and C++ languages. [What must a C compiler do when it finds an error?](https://software.codidact.com/q/277340). (more) |
— | about 4 years ago |
| Comment | Post #279382 |
@moony So code golf is all about abusing undefined behavior then find some crapiler that will crapile the code into a non-conforming binary in another non-standard language than the one stated? (more) |
— | about 4 years ago |
| Comment | Post #279382 |
@Quintec Nope, it's too much spyware for me. Anyway, other users might want to read these comments too. (more) |
— | about 4 years ago |
| Comment | Post #279382 |
@dzaima Freestanding mode doesn't mean changing the system or standard lib behavior. It means running programs without the need for an OS, or run a program that is the OS. For this reason, such programs are not called by an OS, but by hardware, such as a power-on reset interrupt vector. This means th... (more) |
— | about 4 years ago |
| Comment | Post #279382 |
"UB doesn't matter if the answer works" The very definition of UB is that you can't prove that something isn't UB with "it seems to be working just fine". [What is undefined behavior and how does it work?](https://software.codidact.com/q/277486) (more) |
— | about 4 years ago |
| Comment | Post #279382 |
"but won't actually compete with GCC/clang" Sure, just run a freestanding port of gcc, which is not a special compiler option, but one of two modes supported: hosted and freestanding. GCC defaults to hosted on hosted systems, but not necessarily so on freestanding systems. `x(){puts("Hello, World!")... (more) |
— | about 4 years ago |
| Comment | Post #279382 |
"it works fine on GCC and clang" No it doesn't, it produces numerous diagnostics on both compilers. See [What must a C compiler do when it finds an error?](https://software.codidact.com/q/277340). What they are executing is not C, but non-standard extensions. (more) |
— | about 4 years ago |
| Comment | Post #279386 |
My point is - your lambda won't run as-is, you need to wrap it in some other code not present. How is that different from calling a function not present? (more) |
— | about 4 years ago |
| Comment | Post #279382 |
And then C has also since the dawn of time allowed freestanding systems with implementation-defined forms to replace main(). So I just need to find some embedded system's compiler that uses the form `x()` instead of main() and now I will win every competition. I can't do that if programs are to be _s... (more) |
— | about 4 years ago |