Namespace

In C++ two variables with the same name are not possible in the same scope i.e a name given to specific type or function represent one entity in a particluar scope but with namespaces, there is a possibility to create two variables or member functions having the same name. A namespace can be defined as a declarative region that is providing a specific scope to the identifiers such as names of the types, function, variables etc which are declared inside it.

Example of Namespace:

#include <iostream>
using namespace std;

namespace first   // Variable created inside namespace
{
	int value = 600;
}

int value = 400;  //A Global variable with same name as variable inside namespace first

int main()
{
	int value = 900;  	// A Local variable with same name as variable inside namespace first

	cout << first::value << '\n'; //Namespace variables can be accessed from outside the namespace using the scope ::
    cout << value << '\n';  //Local variable with same name as namespace variable will be accessed

	return 0;
}

Output:

600
900