# StringTools StringTools offers useful tools for the std::string type. ## Interface
    template <typename Iterator>
    std::string to_string(Iterator first, const Iterator last)
| Returns a string-representation of the values in the range first - last, surrounded by parenthesis and separated by commas.
    void to_lower(std::string &str)
| Transform string str into lower-case.
    void to_upper(std::string &str)
| Transform string str into UPPER-case.