Question

I’m having a bit of difficulty setting up a regex to match a URL using the regex.h library in C. I have a working IP regex that I was hoping to convert to match a simple string such as www.alphanumerictext12.com|edu|org. Something is wrong with my syntax in the regex definition itself.

Below is the working IPREGEX code and my attempted URL regex.

#define IPEXPR    "([0-9]{1,3})\\.([0-9]{1,3})\\.([0-9]{1,3})\\.([0-9]{1,3})"
#define URLEXPR "(www)\\.((?:[a-z][a-z]*[0-9]+[a-z0-9]*))\\.(com|edu|org)"

regex_t regex;

if(regcomp(&regex, IPEXPR, REG_EXTENDED) != 0)
  return 0;

if(regexec(&regex, inputURL, 0, NULL, 0) != 0)
  return 0;

Answer 1

Try:

"www\\.[a-z]+[a-z0-9]*\\.(com|edu|org)"

I removed the [0-9]+ and replaced [a-z][a-z]* with [a-z]+.