C++命名空间使用代码

 1 #pragma once
 2 #include <string>
 3 
 4 namespace pers
 5 {
 6     using namespace std;
 7     struct Person
 8     {
 9         string fname;
10         string lname;
11     };
12     void getPerson(Person &);
13     void showPerson(const Person &);
14 }
15 
16 namespace debts
17 {
18     using namespace pers;
19     struct  Debt
20     {
21         Person name;
22         double amount;
23     };
24     void getDebt(Debt &);
25     void showDebt(const Debt &);
26     double sumDebts(const Debt ar[], int n);
27 }

 1 #include "namesp.h"
 2 #include <iostream>
 3 
 4 using namespace std;
 5 
 6 void pers::getPerson(Person & rp)
 7 {
 8     cout << "Enter first name: ";
 9     cin >> rp.fname;
10     cout << "Enter last name: ";
11     cin >> rp.lname;
12 }
13 
14 void pers::showPerson(const Person & rp)
15 {
16     cout << rp.fname << ", " << rp.lname;
17 }
18 
19 void debts::getDebt(Debt & rd)
20 {
21     getPerson(rd.name);
22     cout << "Enter debt: ";
23     cin >> rd.amount;
24 }
25 
26 void debts::showDebt(const Debt & rd)
27 {
28     showPerson(rd.name);
29     cout << ": $" << rd.amount << endl;
30 }
31 
32 double debts::sumDebts(const Debt ar[], int n)
33 {
34     double total = 0;
35     for (int i = 0; i < n; i++)
36     {
37         total += ar[i].amount;
38     }
39     return total;
40 }

 1 #include <iostream>
 2 #include "namesp.h"
 3 
 4 void other(void);
 5 void another(void);
 6 
 7 int main()
 8 {
 9     using debts::Debt;
10     using debts::showDebt;
11 
12     Debt golf = { {"Benny","Goatsniff"},120.0 };
13     showDebt(golf);
14     other();
15     another();
16     
17     std::cin.get();
18     return 0;
19 }
20 
21 void other(void)
22 {
23     using namespace std;
24     using namespace debts;
25 
26     Person dg = { "Doodles","Glister" };
27     showPerson(dg);
28     cout << endl;
29 
30     Debt zippy[3];
31     int i;
32     for (int i = 0; i < 3; i++)
33     {
34         getDebt(zippy[i]);
35     }
36     for (i = 0; i < 3; i++)
37     {
38         showDebt(zippy[i]);
39     }
40     cout << "Total debt: $" << sumDebts(zippy, 3) << endl;
41     return;
42 }
43 
44 void another(void)
45 {
46     using pers::Person;
47     Person collector = { "Milo","Rightshift" };
48     pers::showPerson(collector);
49     std::cout << std::endl;
50 }