Generate Email address Regex

Question

I'm trying today to build a regex to make it match to email adress.

I've made one but not working in all the cases I want.

I would a Regex to match with all email address finishing with 2 characters after the dot or only the .com.

I hope to be clear enought,

aaaaaa@bbbb.uk --> should work
aaaaaa@bbbb.com --> should work
aaaaaa@bbbb.cc --> should work
aaaaaa@bbbb.ukk --> should not work
aaaaaa@bbbb. --> should not work

this is my code:

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

int main (void)
{
  int match;
  int err;
  regex_t preg;
  regmatch_t pmatch[5];
  size_t nmatch = 5;
  const char *str_request = "1aaaak@aaaa.ukk";

  const char *str_regex = "[a-zA-Z0-9][a-zA-Z0-9_.]+@[a-zA-Z0-9_]+.[a-zA-Z0-9_.]+[a-zA-Z0-9]{2}";          

  err = regcomp(&preg, str_regex, REG_EXTENDED);
  if (err == 0)
    {
      match = regexec(&preg, str_request, nmatch, pmatch, 0);
      nmatch = preg.re_nsub;
      regfree(&preg);
      if (match == 0)
    {
          printf ("match\n");
          int start = pmatch[0].rm_so;
          int end  = pmatch[0].rm_eo;
          printf("%d - %d\n", start, end);
    }
      else if (match == REG_NOMATCH)
    {
          printf("unmatch\n");
    }
}
  puts ("\nPress any key\n");
  getchar ();
  return (EXIT_SUCCESS);
 }

If you search a little you will find *thousands* of variants of regular expressions to validate email addresses. — Some programmer dude, Apr 14 '16 at 12:50
Try `^[a-zA-Z0-9][a-zA-Z0-9_.]+@([a-zA-Z0-9_]+\.)+(uk|c(om|c))$` — Wiktor Stribiżew, Apr 14 '16 at 12:53
@Morovaille stackoverflow.com/a/17692873/4498831 is bad, TLDs have not been nlimited to 6 characters for a long time. — Alex K., Apr 14 '16 at 12:55
Thanks a lot Wiktor for your answer but I don't want to only match with the .uk. It must match with .aa .uk .fr and all dot and 2 letters after it and also .com — joelmoluni, Apr 14 '16 at 12:56
There are hundreds of TLDs like .uk, .com. .net, .pictures - too many for a regex imo. — Alex K., Apr 14 '16 at 12:57
@AlexK. I posted a random answer about the subject, but as Joachim Pileborg wrote, there a thousands topics about it on the net, including SO. I'm pretty sure there is a suitable answer in SO. — Boiethios, Apr 14 '16 at 12:57
I just need a regex to match to all the .aa and also the .com — joelmoluni, Apr 14 '16 at 13:04

Boiethios · Answer 1 · 2016-04-14T13:40:11.437

0

"[a-zA-Z0-9][a-zA-Z0-9_.]+@[a-zA-Z0-9_]+\\.(com|[a-zA-Z]{2})$"

https://regex101.com/ is a very good tool for that

\. means a litteral dot ;

(|) means an alternative ;

$ means the end of the line, as we do not want some trailing chars after the match.

edited Apr 14 '16 at 13:40

answered Apr 14 '16 at 13:13

Boiethios

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is it working for you Moravaille ? – joelmoluni Apr 14 '16 at 13:21
I tried it on the site, and it worked, yes. – Boiethios Apr 14 '16 at 13:24
I edited it : I forgot the end of line. – Boiethios Apr 14 '16 at 13:25
I've tried it on my code, replacing the .\ by .\\ to enable the gcc error main.cpp:25:27: warning: unknown escape sequence: '\.' [enabled by default] and it's matching every time, it's matching for aaaa@bbb.cccc and also aaaa@bbbb.ccc.. – joelmoluni Apr 14 '16 at 13:26
I edited it, retry, it works. – Boiethios Apr 14 '16 at 13:30
Thanks Moravaille, it's well working. Could you tell me what mean the $ at the end ? – joelmoluni Apr 14 '16 at 13:37
You are welcome :) I edited for `$`. Please valid the answer if it works. – Boiethios Apr 14 '16 at 13:40
Does someone know why is not matching to this line ? _ MR NOURS _ – joelmoluni Apr 21 '16 at 09:17
I do not understand the question. – Boiethios Apr 21 '16 at 10:53

Generate Email address Regex

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