Namespaces prevent naming conflicts by putting functions in their own "zone".

To just use one function of a namespace, you could do this:

std::cout << "std is a namespace" << endl;

In the above line, std is a namespace.

Using Namespaces

But if you don't want to write "std::" infront of each item from the std namespace, you could do this:

using namespace std;
cout << "std is a namespace" << endl;

You can 'use' two or more namespaces at the same time. For example :

using namespace gdn;
using namespace std;

This is fine so long as there are no functions or classes that have the same name in both namespaces.

Declarations

You can make single functions of a namespace local (rather than the whole thing) by using a declaration :

using std::cout;
using std::cin;
using std::endl;

Creating a Namespace

To make your own namespaces, you can do this:

namespace position
{
    int get_position();
    void set_position(int x, int y);
}

Extending Namespaces

You can include more functions in a namespace from a library, but it's advisable not to.