Nested namespace

Write a program to show nested 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()
{
	cout << "a = " << A::a << endl;
	cout << "b = " << A::a << endl;
	A::My_Fun();
	cout << "a = " << A::B::a << endl;
	cout << "b = " << A::B::a << endl;
	A::B::My_Fun();
	return 0;
}

Output

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