C++primer 15.2.1节练习

 1 #include <iostream>
 2 #include <string>
 3 #include <utility>
 4 #include <memory>
 5 #include <vector>
 6 
 7 using namespace std;
 8 
 9 class Quote {
10 public:
11     Quote() = default;
12     Quote(const string &book, double sales_price) : bookNo(book), price(sales_price) {}
13     string isbn() { return bookNo; }
14     virtual double net_price(size_t n) const{ return n * price; }
15     virtual ~Quote() = default;
16 private:
17     string bookNo;
18 protected:
19     double price = 0.0;
20 };
21 
22 double print_total(ostream& os, const Quote& item, size_t t);
23 
24 int main()
25 {
26     
27     system("pause");
28     return 0;
29 }
30 
31 double print_total(ostream & os, const Quote &item, size_t t)
32 {
33     double ret = item.net_price(t);
34     os << "ISBN: " << item.isbn << " # sold: " << t << " total due: " << ret << endl;
35     return ret;
36 }