Easier nested namespace syntax

Until the C++14 standard, the syntax supported for a nested namespace in C++ was as follows:

#include <iostream>
using namespace std;

namespace org {
    namespace tektutor {
        namespace application {
             namespace internals {
                  int x;
             }
        }
    }
}

int main ( ) {
    org::tektutor::application::internals::x = 100;
    cout << "\nValue of x is " << org::tektutor::application::internals::x << endl;

    return 0;
}

The preceding code can be compiled and the output can be viewed with the following commands:

g++-7 main.cpp -std=c++17
./a.out

The output of the preceding program is as follows:

Value of x is 100

Every namespace level starts and ends with curly brackets, which makes it difficult to use nested namespaces in large applications. C++17 nested namespace syntax is really cool; just take a look at the following code and you will readily agree with me:

#include <iostream>
using namespace std;

namespace org::tektutor::application::internals {
    int x;
}

int main ( ) {
    org::tektutor::application::internals::x = 100;
    cout << "\nValue of x is " << org::tektutor::application::internals::x << endl;

    return 0;
}

The preceding code can be compiled and the output can be viewed with the following commands:

g++-7 main.cpp -std=c++17
./a.out

The output remains the same as the previous program:

Value of x is 100