regex/regexiter1.cpp

The following code example is taken from the book
The C++ Standard Library - A Tutorial and Reference, 2nd Edition
by Nicolai M. Josuttis, Addison Wesley Longman, 2012
Copyright © 2012 by Pearson Education, Inc. and Nicolai M. Josuttis


#include <string>
#include <regex>
#include <iostream>
#include <algorithm>
using namespace std;

int main()
{
    string data = "<person>\n"
                  " <first>Nico</first>\n"
                  " <last>Josuttis</last>\n"
                  "</person>\n";

    regex reg("<(.*)>(.*)</(\\1)>");

    // iterate over all matches (using a regex_iterator):
    sregex_iterator pos(data.cbegin(),data.cend(),reg);
    sregex_iterator end;
    for ( ; pos!=end ; ++pos ) {
        cout << "match:  " << pos->str() << endl;
        cout << " tag:   " << pos->str(1) << endl;
        cout << " value: " << pos->str(2) << endl;
    }

    // use a regex_iterator to process each matched substring as element in an algorithm:
    sregex_iterator beg(data.cbegin(),data.cend(),reg);
    for_each (beg,end,[](const smatch& m) {
                          cout << "match:  " << m.str() << endl;
                          cout << " tag:   " << m.str(1) << endl;
                          cout << " value: " << m.str(2) << endl;
                      });
}