Parse delimited string in C++

gistfile1.txt

size_t split(std::string s, std::vector<std::string>& tokens,
             std::string delim ="\t\n ")
{
   tokens.clear();
   size_t pos = s.find_first_not_of(delim);
   while (pos != std::string::npos)
   {
      size_t next = s.find_first_of(delim, pos);
      if (pos == std::string::npos)
         tokens.emplace_back(s.substr(pos));
      else
      {
         tokens.emplace_back(s.substr(pos, next-pos));
         pos = s.find_first_not_of(delim, next);
      }
   }
   return tokens.size();
}