CODEWITHSUNDEEP
cregexarrays
gzix
gzix

Reputation: 269

C programming- Regex matching and store in string

I am able to match patterns using regex library in C. The matched words can be printed. But, i need to store the matches into a string or char array. The code is below:

void match(regex_t *pexp, char *sz) {
regmatch_t matches[MAX_MATCHES]; //A list of the matches in the string (a list of 1)
  if (regexec(pexp, sz, MAX_MATCHES, matches, 0) == 0) 
  {
    printf("%.*s\n", (int)(matches[0].rm_eo - matches[0].rm_so), sz + matches[0].rm_so);        
  }
  else {
    printf("\"%s\" does not match\n", sz);
   }
 }

int main() {
int rv;
regex_t exp;
rv = regcomp(&exp, "-?([A-Z]+)", REG_EXTENDED);
if (rv != 0) {
    printf("regcomp failed with %d\n", rv);
}
match(&exp, "456-CCIMI");
regfree(&exp);
return 0;
}

OR may be just i need this. How can i splice char array in C? ie. if a char array has "ABCDEF" 6 characters. I just need the chars in index 2 to index 5 "CDEF".

Upvotes: 0

Views: 1122

Answers (3)

jogh
jogh

Reputation: 31

For the example you provided, if you want -CCIMI, you can

strncpy(dest, sz + matches[0].rm_so, matches[0].rm_eo - matches[0].rm_so);

But since you used group in pattern, I guess what you really want is just CCIMI. You can 

strncpy(dest, sz + matches[1].rm_so, matches[1].rm_eo - matches[1].rm_so);

Before strncpy(), please do malloc sufficient space for dest

Upvotes: 3

Nish
Nish

Reputation: 379

you can use strncpy also, if you are looking for a string function.

strncpy(dest, sz + matches[0].rm_so, matches[0].rm_eo - matches[0].rm_so);

Upvotes: 0

Some programmer dude
Some programmer dude

Reputation: 409442

You can use memcpy to copy the matched string to an array, or dynamically allocate a string:

char *dest;

/* your regexec call */

dest = malloc(matches[0].rm_eo - matches[0].rm_so + 1);  /* +1 for terminator */

memcpy(dest, sz + matches[0].rm_so, matches[0].rm_eo - matches[0].rm_so);

dest[matches[0].rm_eo - matches[0].rm_so] = '\0';  /* terminate the string */

After the above code, dest points to the matched string.

Upvotes: 1

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