#include <boost/regex.hpp>
#include <string>
#include <iostream>

// needs to link with this lib
// -lboost_regex

int main(int argc, char** argv)
{
  std::string fn;
  boost::regex expression(".*txt");

  std::cout << "Enter a file name: ";
  std::cin >> fn;

  if (boost::regex_match(fn, expression))
  {
    std::cout << "its a text file" << std::endl;
  }

  return 0;
}