Declarative namespace

Write a program to show the use case of the declarative namespace.

#include<iostream>
using namespace std;
namespace A
{
	int a = 1;
	int b = 2;
	void My_Fun()
	{
		cout << "inside namespace A" << endl;
	}
}
namespace B
{
	int a = 3;
	int b = 4;
	void My_Fun()
	{
		cout << "inside namespace B" << endl;
	}
}
int a = 5;
int b = 23;
int main()
{
	cout << "a = " << a << endl;
	cout << "b = " << b << endl;
	using A :: a;
	using B :: b;
	using B :: My_Fun;
	cout << "a = " << a << endl;
	cout << "b = " << b << endl;
	My_Fun();
	return 0;
}

Output

a = 5
b = 23
a = 1
b = 4
inside namespace B