Namespace: Namespace defines a scope for the identifiers that are used in the program. To use we will do the following
using namespace namespace_name;
here, at namespace_name we will give the name of the namespace we want to use. Supposing that we are writing the following,
using namespace std;
here, std is the namespace where ANSI C++ standard class libraries are defined. This will bring all the identifiers defined in std to the current global scope. We can also create namespace in following format,
namespace namespace_name{
/*Declaration of variables,
functions, classes etc should be given here*/
}