C : Access violation reading location 0x00000044

I have a file with heading [what],[where],[who] and I put it into an array list. I am trying to concatenate the bracket and the array of words together. like [ what ] but error will pop up.

" Exception thrown at 0x0F20EDD0 (ucrtbased.dll) in project.exe: 0xC0000005: Access violation reading location 0x00000044 "

char intent[255];
char inv[3][10] = { "what","where","who" };

//char stringCat = strncat(intent, inv[0],10);
snprintf(intent, sizeof(intent), "[%s]", inv[0]);

can I know why does this happen?

intent[0] is a char, not a char *. strcat will append to the end of the char * pointed to in the first argument, so you are getting an error. Changing to strcat(intent, inv[0]) will fix this immediate problem, but the code will still be wrong.

You need the string to be nil-terminated, so you need intent[1] = '\0' prior to the strcat().

strcat also simply writes to the end of intent, so stringCat and totalCat are pointless variables--they simply point to intent.

You would also do better to use strncat() than strcat() to prevent buffer overruns.