cpp_primer_5th_edition_exercises/Chapter07/7.41/Sales_data.h at main · trapperdot00/cpp_primer_5th_edition_exercises · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
#ifndef SALES_DATA_H
#define SALES_DATA_H

#include <string>
#include <iostream>

class Sales_data;
std::istream &read(std::istream&, Sales_data&);

class Sales_data {
	friend std::istream &read(std::istream &, Sales_data &);
	friend std::ostream &print(std::ostream &, const Sales_data &);
public:
	Sales_data() : Sales_data("", 0, 0)
		{ std::cout << "Sales_data()" << std::endl; }
	Sales_data(const std::string &s) : Sales_data(s, 0, 0)
		{ std::cout << "Sales_data(const std::string &)" << std::endl; }
	Sales_data(const std::string &s, unsigned n, double p) : bookNo(s), units_sold(n), revenue(p * n)
		{ std::cout << "Sales_data(const std::string &, unsigned, double)" << std::endl; }
	Sales_data(std::istream &is)
		{ std::cout << "Sales_data(std::istream &)" << std::endl; read(is, *this); }

	Sales_data &combine(const Sales_data&);
	std::string isbn() const { return bookNo; }
	inline double avg_price() const;

private:
	std::string bookNo;
	unsigned units_sold = 0;
	double revenue = 0.0;
};

Sales_data add(const Sales_data&, const Sales_data&);
std::ostream &print(std::ostream&, const Sales_data&);

inline double Sales_data::avg_price() const {
	if (units_sold)
		return revenue / units_sold;
	else
		return 0;
}

#endif