What are namespaces?

Namespaces in C++

Suppose in your group of friends, you have two people with the same name, say ‘A’. Now every time you call A they both get confused if you are calling him or the other A. To resolve this anomaly, you start using their full names. Namespaces in C++ work in the same manner.

Namespaces provide a method of preventing name conflicts in large projects. Variables and functions having the same name can be differentiated using namespaces.

For example,

#include <iostream>
using namespace std;

namespace one{
	int val = 512;
}

namespace two{
	float val = 3.13;
}

int main(){
	cout << one::val;
	cout << "\n" << two::val;
	return 0;
}

Output

512

3.13

More about namespaces:

1. Namespaces is a feature of C++ and is not available in C.
2. Namespaces can be declared only globally
3. Multiple namespace blocks with the same name are allowed
4. Namespace declarations can be nested inside another namespace.
5. Namespace don’t use access specifiers i.e public, private
6. To avoid writing the name of namespace again and again we can use the keyword using that specifies a default namespace over a block it is declared. example, using namespace std;