Modern C++: Efficient and Scalable Application Development

How to do it...

In order to search for occurrences of a regular expression through a string you should perform the following:

1. Include headers <regex> and <string> and the namespace std::string_literals for C++14 standard user-defined literals for strings:

        #include <regex>         #include <string>         using namespace std::string_literals;

2. Use raw string literals to specify the regular expression to avoid escaping backslashes (that can occur frequently). The following regular expression validates the file format proposed earlier:

        auto pattern {R"(^(?!#)(\w+)\s*=\s*([\w\d]+[\w\d._,\-:]*)$)"s};

3. Create an std::regex/std::wregex object (depending on the character set that is used) to encapsulate the regular expression:

 auto rx = std::regex{pattern}; ...