#ifndef _QUOTE_H
#define _QUOTE_H

class Quote
{
friend std::ostream& operator<<(std::ostream&, const Quote &);
public:
    Quote() = default;
    Quote(const std::string &book, double sales_price):
        bookNo(book), price(sales_price) {}
    std::string isbn() const { return bookNo; }
    virtual double net_price(std::size_t n) const
    { return n * price; }
    virtual ~Quote() = default;
private:
    std::string bookNo;
protected:
    double price = 0.0;
};

#endif