filling array of strings

[wicked halo]

hi i trying fill 2d array with strings (i want split a big input string by paragraphs) but i get abort trap 6:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main() {
  char* input = getenv("AOC_INPUT");

  const char* paragraphs[8];
  int nextParagraphIndex = 0;

  const char* delimiter = "\n\n";

  char* paragraph = strtok(input, delimiter);

  while (paragraph != NULL) {
    paragraphs[nextParagraphIndex] = paragraph;
    ++nextParagraphIndex;
    paragraph = strtok(NULL, delimiter);
  }
}

[shut otter]

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[silk finch]

In your while loop you should be checking for the null terminator ‘\0’

Oh never mind, you’re not looping through every character

[vivid dirge]

Where is your 2d array?
All you have is a 1d array of size 8 of char pointers.
I mean yes, that is a possible way to store strings, but it's fundamentally different from a 2d array.

Since I'm on my phone and can't test right now, please post the full error message. If that was the full error message then please compile with -fsanitize=address for a potentially better error message

[wicked halo]

it say is no good

[wicked halo]

array of array of char

[silk finch]

Yea I didn’t read it all the way

[wicked halo]

oh yes i meant array 1d of string

[wicked halo]

main(65008,0x10e020600) malloc: nano zone abandoned due to inability to preallocate reserved vm space.
=================================================================
==65008==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7ff7ba3876a0 at pc 0x000105b79d76 bp 0x7ff7ba387630 sp 0x7ff7ba387628
WRITE of size 8 at 0x7ff7ba3876a0 thread T0
    #0 0x105b79d75 in main+0x165 (main:x86_64+0x100003d75)
    #1 0x10dfa552d in start+0x1cd (dyld:x86_64+0x552d)

Address 0x7ff7ba3876a0 is located in stack of thread T0 at offset 96 in frame
    #0 0x105b79c1f in main+0xf (main:x86_64+0x100003c1f)

  This frame has 1 object(s):
    [32, 96) 'paragraphs' <== Memory access at offset 96 overflows this variable
HINT: this may be a false positive if your program uses some custom stack unwind mechanism, swapcontext or vfork
      (longjmp and C++ exceptions *are* supported)
SUMMARY: AddressSanitizer: stack-buffer-overflow (main:x86_64+0x100003d75) in main+0x165
Shadow bytes around the buggy address:
  0x1ffef7470e80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1ffef7470e90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1ffef7470ea0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1ffef7470eb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1ffef7470ec0: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00
=>0x1ffef7470ed0: 00 00 00 00[f3]f3 f3 f3 00 00 00 00 00 00 00 00
  0x1ffef7470ee0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1ffef7470ef0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1ffef7470f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1ffef7470f10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1ffef7470f20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
==65008==ABORTING
sh: line 1: 65008 Abort trap: 6           ./main```

filling array of strings

[vivid dirge]

Put a print (and a fflush(stdout); afterwards to ensure the print happens) to observe how large your nextParagraphIndex value grows.

I have a feeling the array size of 8 may not be sufficiently large.

[wicked halo]

ok i tried const char** paragraphs = malloc(8 * sizeof(char*)); and it work thakns!

i didnt know malloc exist

!sloved

[vivid dirge]

How does that work but the version before didn't?

[vivid dirge]

Btw, you made a typo here

[shut sleet]

strtok is going to modify input, so depending on where input points, you may have a write access permission problem. I am not certain about behaviour guarantees when modifying memory returned by getenv().

Secondarily the second parameter of strtok() is not a delimiter string, it is a list of delimiter characters.

If this was your input:

abc\n\ndef\nghi\njkl\n\n\n\nmno\npqr\nstu\n

Your loop would return an an array of pointers into this same string that would now look like this:

(gdb) inspect input
$3 = "abc\000\ndef\000ghi\000jkl\000\n\n\nmno\000pqr\000stu\000"

And your paragraphs array would look like this:

(gdb) inspect paragraphs
$4 = {0x7fffffffe470 "abc", 0x7fffffffe475 "def", 0x7fffffffe479 "ghi", 0x7fffffffe47d "jkl", 0x7fffffffe484 "mno", 0x7fffffffe488 "pqr", 0x7fffffffe48c "stu", 0x0}

This finds all non-null strings delimited by newlines rather than the paragraphs.

[wicked halo]

bruh i just want to fill an arrya with strings how is this not a solved problem 😭

[shut sleet]

no worries mate. if you are happy with the strings you got, good on-ya. It just doesn't match the description of the problem you provided. Disregard.

[wicked halo]

!solved