Directive namespace

Write a program to demonstrate the use of directive 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 main()
{
	{
		using namespace A;
		cout << "a = " << a << endl;
		cout << "b = " << b << endl;
		My_Fun();
	}
	using  namespace B;
	cout << "a = " << a << endl;
	cout << "b = " << b << endl;
	My_Fun();
	return 0;
}

Output

a = 1
b = 2
inside namespace A
a = 3
b = 4
inside namespace B