C++命名空间使用代码

namesp.h

 #pragma once
 #include <string>

 namespace pers
 {
     using namespace std;
     struct Person
     {
         string fname;
         string lname;
     };
     void getPerson(Person &);
     void showPerson(const Person &);
 }

 namespace debts
 {
     using namespace pers;
     struct  Debt
     {
         Person name;
         double amount;
     };
     void getDebt(Debt &);
     void showDebt(const Debt &);
     double sumDebts(const Debt ar[], int n);
 }

namesp.cpp

 #include "namesp.h"
 #include <iostream>

 using namespace std;

 void pers::getPerson(Person & rp)
 {
     cout << "Enter first name: ";
     cin >> rp.fname;
     cout << "Enter last name: ";
     cin >> rp.lname;
 }

 void pers::showPerson(const Person & rp)
 {
     cout << rp.fname << ", " << rp.lname;
 }

 void debts::getDebt(Debt & rd)
 {
     getPerson(rd.name);
     cout << "Enter debt: ";
     cin >> rd.amount;
 }

 void debts::showDebt(const Debt & rd)
 {
     showPerson(rd.name);
     cout << ": $" << rd.amount << endl;
 }

 double debts::sumDebts(const Debt ar[], int n)
 {
     double total = ;
     for (int i = ; i < n; i++)
     {
         total += ar[i].amount;
     }
     return total;
 }

namessp.cpp

 #include <iostream>
 #include "namesp.h"

 void other(void);
 void another(void);

 int main()
 {
     using debts::Debt;
     using debts::showDebt;

     Debt golf = { {"Benny","Goatsniff"},120.0 };
     showDebt(golf);
     other();
     another();

     std::cin.get();
     return ;
 }

 void other(void)
 {
     using namespace std;
     using namespace debts;

     Person dg = { "Doodles","Glister" };
     showPerson(dg);
     cout << endl;

     Debt zippy[];
     int i;
     for (int i = ; i < ; i++)
     {
         getDebt(zippy[i]);
     }
     for (i = ; i < ; i++)
     {
         showDebt(zippy[i]);
     }
     cout << "Total debt: $" << sumDebts(zippy, ) << endl;
     return;
 }

 void another(void)
 {
     using pers::Person;
     Person collector = { "Milo","Rightshift" };
     pers::showPerson(collector);
     std::cout << std::endl;
 }