text: #ifndef __PRODUCT_H
  #define __PRODUCT_H
  
  #include <iostream>
  #include <fstream>
  class Product {
    public: 
      Product(std::string name, double price, std::string description);
      friend std::ostream& operator<<(std::ostream& ost, const Product& product);
      Product(std::istream& ist);
      virtual void save(std::ostream& ost);
      int price();
    protected:
      virtual std::string to_string() const;
    private:
      static int _nextsn;
      std::string _name;
      int _stocknum;
      double _price;
      std::string _description;
  };
  
  #endif
  