regex_token_iterator_0.cpp

#include <regex>
#include <algorithm>
#include <iostream>

int main()
{
    std::string str("version 1.20.300.400");
    std::regex pattern("([0-9]+)\\.([0-9]+)\\.([0-9]+)\\.([0-9]+)");
    {
        std::sregex_token_iterator begin(str.begin(), str.end(), pattern, {1,3});
        std::sregex_token_iterator end;
        std::for_each(begin, end, [](const std::string& sub) {
             std::cout << sub << std::endl; // 1 and 300
        });
    }
    {
        std::sregex_token_iterator begin(str.begin(), str.end(), pattern, {2,4});
        std::sregex_token_iterator end;
        std::for_each(begin, end, [](const std::string& sub) {
             std::cout << sub << std::endl; // 20 and 400
        });
    }
    {
        std::sregex_token_iterator begin(str.begin(), str.end(), pattern, 0);
        std::sregex_token_iterator end;
        std::for_each(begin, end, [](const std::string& sub) {
             std::cout << sub << std::endl; // 1.20.300.400
        });
    }
    {
        std::sregex_token_iterator begin(str.begin(), str.end(), pattern, -1);
        std::sregex_token_iterator end;
        std::for_each(begin, end, [](const std::string& sub) {
             std::cout << sub << std::endl; // version
        });
    }
    return 0;
}