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
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
|
#include <iostream>
/*
*
* 7.41
*
*
*/
struct SalesData;
SalesData add(const SalesData&, const SalesData&);
std::ostream &print(std::ostream&, const SalesData&);
std::istream &read(std::istream&, SalesData&);
struct SalesData {
SalesData(const std::string &s, unsigned n, double p): // constructor, both bookno, UnitsSold and Revenue
BookNo(s), UnitsSold(n), Revenue(p*n) { }
SalesData(): SalesData("", 0, 0) { std::cout << "delegated\n"; }
SalesData(const std::string &s): SalesData(s, 0, 0) { std::cout << "delegated\n"; }
SalesData(const std::string &s, unsigned ui): SalesData(s, ui, 0) { std::cout << "delegated\n"; }
SalesData(std::istream &sdcin): SalesData() { read(sdcin, *this); std::cout << "delegated\n"; }; // Constructor, but read from istream
std::string isbn() const { return BookNo; } // member function
SalesData &combine(const SalesData&); // member function, defined elsewhere
inline double avg_price() const; // member function, defined elsewhere
std::string BookNo; // data member
unsigned int UnitsSold = 0; // data member
double Revenue = 0.0; // data member
};
inline double SalesData::avg_price() const {
if (UnitsSold)
return Revenue / UnitsSold;
else
return 0;
}
SalesData& SalesData::combine(const SalesData &rhs) {
UnitsSold += rhs.UnitsSold;
Revenue += rhs.Revenue;
return *this;
}
std::istream &read(std::istream &is, SalesData &item) { // Not member function
double price = 0;
is >> item.BookNo >> item.UnitsSold >> price;
item.Revenue = price * item.UnitsSold;
return is;
}
std::ostream &print(std::ostream &os, const SalesData &item) { // Not member function
os << item.isbn() << " " << item.UnitsSold << " "
<< item.Revenue << " " << item.avg_price();
return os;
}
SalesData add(const SalesData sd1, const SalesData sd2) { // Not member function
SalesData sdsum = sd1;
sdsum.combine(sd2);
return sdsum;
}
int main () {
SalesData a;
SalesData b("WOW");
SalesData c("Woo", 23);
SalesData d("Woohoo", 33, 10);
SalesData e(std::cin);
return 0;
}
|
