Regex C++: extract substring

Question

I would like to extract a substring between two others.
ex: /home/toto/FILE_mysymbol_EVENT.DAT
or just FILE_othersymbol_EVENT.DAT
And I

Answer 1

I would study corner cases before trusting it, but

   std::string text = "/home/toto/FILE_mysymbol_EVENT.DAT";
   std::regex re("(.*)(FILE_)(.*)(_EVENT.DAT)(.*)");
   std::cout << std::regex_replace(text, re, "$3") << '\n';

is a good candidate.