15.2.1节练习
【练习15.3】
1 class Quote 2 { 3 public: 4 Quote() = default; 5 Quote(const string &book,double sales_price): bookNO(book), price(sales_price) {} 6 std::string isbn() { return bookNo; } 7 virtual double net_price(std::size_t n) const 8 9 private: 10 std::string bookNo; //书籍的ISBN编号 11 12 protected: 13 double price = 0.0; //代表普通状态下不打折的价格 14 }
1 double print_total(ostream &os, const Quote &item, size_t n) 2 { 3 double ret = item.net_price; //根据传入item形参类型调用的Quote::net_price()或者Bulk_quote::net_price 4 os << "ISBN: " << item.isbn() //调用Quote::isbn 5 << " # sold: " << n << "total due: " << ret << endl; 6 }