| 4 Oct 2022 |
 ahto | In reply to @trans_panda:matrix.org
I think I read about this problem. prime numbers are some difficult math stuff that only appears in college problems. IRL I think people just use pre-computed maps and whatnot. I could be wrong though Difficult to compute quickly but not a difficulty concept | 20:03:32 |
 trans_panda 🏳️⚧️ (they/them) | int isprime(int a) {
int i, j;
for (i = a - 1; i > 0; i--) {
for (j = a - 1; j > 0; j--) {
if ((j * i) == a)
return 1;
}
}
return 0;
}
| 20:04:41 |
| trans_panda 🏳️⚧️ (they/them) | somthing like this? | 20:04:45 |
| trans_panda 🏳️⚧️ (they/them) | I never went to computer school to see these problems irl | 20:04:59 |
|  @layap:matrix.org joined the room. | 21:49:30 |
| @layap:matrix.org left the room. | 21:54:03 |
| 5 Oct 2022 |
 huayra1 | you should check to make sure a is a sane value. signed integer overflow is undefined | 00:59:15 |
| huayra1 | if the value was -((2^32)+1), it could overflow | 01:00:37 |
| huayra1 | a little pedantic, but you should also use int32_t, etc | 01:01:12 |
| huayra1 | i'm going to assume the compiler will do the rest of the optimizations regarding bit hacks and such | 01:05:09 |
| huayra1 | * i'm going to assume the compiler will do the rest of the optimizations regarding bit hacks and such (for something this simple, there is much to do anyways) | 01:05:39 |
| huayra1 | * i'm going to assume the compiler will do the rest of the optimizations regarding bit hacks and such (for something this simple, there is not much to do anyways) | 01:05:48 |
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 hnhx | what would be the best way to empty an array like this? char foo[10240][256];
this is what i do rn: memset(entry_list, 0, 10240);
is this good, or should i do something else? | 10:01:04 |
| hnhx | * what would be the best way to empty an array like this? char foo[10240][256];
this is what i do rn: memset(foo, 0, 10240);
is this good, or should i do something else? | 10:01:17 |
 those who know me have no need of my name | Arrays are never empty. A loop is usually acceptable too. | 10:08:21 |
 NRK | In reply to@admin:beparanoid.de
what would be the best way to empty an array like this? char foo[10240][256];
this is what i do rn: memset(foo, 0, 10240);
is this good, or should i do something else? memset takes size in bytes | 11:50:04 |
| NRK | it should've been `memset(foo, 0, sizeof foo);` instead | 11:50:30 |
| NRK | but if you're trying to *initialize* it, as opposed to resetting it, you can just initialize the first element to 0, the rest of the elements will be implicitly zero-ed. | 11:51:11 |
| NRK | `char buf[256] = {0};` | 11:51:22 |
| hnhx | ah okay thanks | 11:55:09 |
 root6 | * read an integer from user
if it is prime number, print "true"
if it isn't prime number, print "false" | 14:40:21 |
|  @matrix_help:matrix.org left the room. | 19:48:05 |
| hnhx | why isnt copy() a syscall when rename() is? (https://man7.org/linux/man-pages/man2/syscalls.2.html) I mean with rename() you can move files with the file content to another path, why doesn't copy() exist then as a syscall? I find this p weird. | 20:31:36 |
 name_missing | I guess atomic and stuff. | 20:33:06 |
| name_missing | Copy is more complex. | 20:33:15 |
| hnhx | how, rename() has a copy in it since it can move files with its content to another path | 20:33:51 |
| hnhx | https://man7.org/linux/man-pages/man2/rename.2.html | 20:34:28 |
| 6 Oct 2022 |
|  @kim_martial:matrix.org joined the room. | 13:35:07 |
| @kim_martial:matrix.org left the room. | 15:56:29 |
