Regular Expression 正则表达式-3 (C++)[3]

        output.append( group[3] );
        output.append( "," );
        output.append( "\n" );
        // update
        start = group[0].second;
        flags |= boost::regex_constants::match_prev_avail;
        flags |= boost::regex_constants::match_not_bob;
    }
    return;
}