Exer17_26.cpp

// Note: this program uses ./data/person_info.
#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
#include <regex>
using std::cout;
using std::endl;
using std::ifstream;
using std::ostringstream;
using std::string;
using std::regex;
using std::smatch;
using std::sregex_iterator;
using std::regex_replace;
using std::regex_constants::format_first_only;
int main(int argc, char* argv[])
{
    if (argc != 2)
        return -1;
    ifstream is(argv[1]);
    string phone = "(\\()?(\\d{3})(\\))?([-. ])?(\\d{3})([-. ])?(\\d{4})";
    regex r(phone); // a regex to find our pattern
    smatch m;
    string s;
    string fmt = "$2.$5.$7 "; // reformat numbers to ddd.ddd.dddd
    // read each record from the input file, write the first match only
    while (getline(is, s)) {
        unsigned i = 0;
        ostringstream os;
        for(sregex_iterator it(s.begin(), s.end(), r), end_it;
            it != end_it; ++it, ++i) {
            if(i == 0)
                os << it->prefix() << it->str() << " ";
            else
                os << it->format(fmt);
        }
        cout << os.str() << endl;
    }
    return 0;
}