main cpp file for Boost regex example

regexExample.cpp

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

int main()
{
std::string line;
boost::regex pat( "^Subject: (Re: |Fw: )*(.*)" );

while (std::cin)
{
std::getline(std::cin, line);
boost::smatch matches;
if (boost::regex_match(line, matches, pat))
std::cout << matches[2] << std::endl;
}
return 0;
}