1. Creation and Use of Namespaces

2. Your First Namespace
// syntax namespace your_namespace_name { code elements to be put in that namespace } // example namespace price double sqrt(const double);

3. Your First Namespace
// syntax namespace your_namespace_name { code elements to be put in that namespace } // example namespace price double sqrt(const double);

4. Your First Namespace
// syntax namespace your_namespace_name { code elements to be put in that namespace } // example namespace price double sqrt(const double);

5. Your First Namespace
// syntax namespace your_namespace_name { code elements to be put in that namespace } // example namespace price double sqrt(const double);

6. Scoping
namespace price { double sqrt(const double); }

7. Scoping namespace price { double sqrt(const double); } option 1
double d = price::sqrt(9);

8. Scoping namespace price { double sqrt(const double); } option 1
double d = price::sqrt(9);
using price::sqrt;
...
double d = sqrt(9);

9. Scoping namespace price { double sqrt(const double); } option 1
double d = price::sqrt(9);
using price::sqrt;
...
double d = sqrt(9);
using namespace price;
...
double d = sqrt(9);

10. Preventing Conflicts namespace price { double sqrt(const double); }
option 1
double d = price::sqrt(9);
double s = std::sqrt(9);

11. Preventing Conflicts namespace price { double sqrt(const double); }
option 1
option 2
double d = price::sqrt(9);
double s = std::sqrt(16);
using price::sqrt;
using std::sqrt;
...
double d = sqrt(9);
double s = sqrt(16);

12. Preventing Conflicts namespace price { double sqrt(const double); }
option 1
option 2
double d = price::sqrt(9);
double s = std::sqrt(16);
using price::sqrt;
using std::sqrt;
...
double d = sqrt(9);
double s = sqrt(16);

13. Preventing Conflicts namespace price { double sqrt(const double); }
option 1
option 2
option 3
double d = price::sqrt(9);
double s = std::sqrt(16);
using price::sqrt;
using std::sqrt;
...
double d = sqrt(9);
double s = sqrt(16);
using namespace price;
using namespace std;
...
double d = sqrt(9);
double s = sqrt(16);

14. Preventing Conflicts namespace price { double sqrt(const double); }
option 1
option 2
option 3
double d = price::sqrt(9);
double s = std::sqrt(16);
using price::sqrt;
using std::sqrt;
...
double d = sqrt(9);
double s = sqrt(16);
using namespace price;
using namespace std;
...
double d = sqrt(9);
double s = sqrt(16);

15. Open Scoping jose.h alicia.h main.cpp #ifndef JOSE_H #define JOSE_H
namespace price {
int jose; }
#endif
#ifndef ALICIA_H
#define ALICIA_H
namespace price {
char alicia; }
#endif
#include “jose.h”
#include “alicia.h”
using namespace price;
int main() {
jose = 16;
alicia = ‘a’;
...

16. Open Scoping array.h array.hpp main.cpp #ifndef ARRAY_H
#define ARRAY_H
#include <iostream>
using std::cout;
using std::endl;
namespace price {
template <typename t>
class array
public:
t m_data[20];
void print(); }; }
#include "array.hpp“
#endif
namespace price {
template <typename t>
void array<t>::print()
int i;
for(i = 0; i < 20; i++)
cout << m_data[i];
cout << ", "; }
cout << endl;
#include "array.h“
using price::array;
int main() {
array<int> a;
a.m_data[0] = 24;
a.print();
return 0; }

17. Open Scoping array.h array.hpp #ifndef ARRAY_H #define ARRAY_H
#include <iostream>
using std::cout;
using std::endl;
namespace price {
template <typename t>
class array
public:
t m_data[20];
void print(); }; }
#include "array.hpp“
#endif
template <typename t>
void price::array<t>::print() {
int i;
for(i = 0; i < 20; i++)
cout << m_data[i];
cout << ", "; }
cout << endl;

18. The Unnamed Namespace array.h array.hpp main.cpp #ifndef ARRAY_H
#define ARRAY_H
#include <iostream>
using std::cout;
using std::endl;
template <typename t>
class array {
public:
t m_data[20];
void print(); };
#include "array.hpp“
#endif
template <typename t>
void array<t>::print() {
int i;
for(i = 0; i < 20; i++)
cout << m_data[i];
cout << ", "; }
cout << endl;
#include "array.h“
int main() {
array<int> a;
a.m_data[0] = 24;
a.print();
return 0; }

19. End of Session