C++ LANGUAGE NESTED NAMESPACE

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C++ LANGUAGE NESTED NAMESPACE

Nested Namespaces 


Namespaces can be nested where you can define one 
namespace inside another namespace as follows: 


namespace namespace_name1 { 
   // code declarations 
   namespace namespace_name2 { 
      // code declarations 
   } 
} 
 
 
You can access members of nested namespace by 
using resolution operators as follows: 


// to access members of namespace_name2 

using namespace namespace_name1::namespace_name2; 
 
// to access members of namespace:name1 

using namespace namespace_name1; 
In the above statements if you are using namespace_name1, 
then it will make elements of namespace_name2 available in 
the scope as follows: 


#include <iostream> 

using namespace std; 
 
// first name space 
namespace first_space{ 
   void func(){ 
      cout << "Inside first_space" << endl; 
   } 
   // second name space 
   namespace second_space{ 
      void func(){ 
         cout << "Inside second_space" << endl; 
      } 
   } 
} 
using namespace first_space::second_space; 
int main () 
{ 
  
   // This calls function from second name space. 
   func(); 
    
   return 0; 
} 

If we compile and run above code, 
this would produce the following result: 

Inside second_space