- void set (const string &header_string, const string &data_string, const string &footer_string);
- virtual string to_string () const;
- virtual string data_string () const;
+ void set (const std::string &header_string, const std::string &data_string, const std::string &footer_string);
+ virtual std::string to_string () const;
+ virtual std::string data_string () const;