string AddressUnparsed = "collectief@test.nl";
smatch matchesAddress;

if (regex_search(AddressUnparsed, matchesAddress, regex("([^@\s]+@[^@\s]+\.[a-zA-Z]{2,})", regex_constants::ECMAScript | regex_constants::icase))) {
    cout << "Match!. The emailaddress is: " << matchesAddress[1] << endl;
}
else {
    cout << "No match!" << endl;
}