A: Multiple providers of libraries might employ common global identifiers causing a name collision whereas an application attempt to link with two or more such libraries. The namespace feature surrounds from library's external declarations along with a unique namespace that remove the potential for those collisions. namespace [identifier] { namespace-body }
A namespace declaration identifies & assigns a name to a declarative region.
The identifier in a namespace declaration has to be unique in the declarative region wherein it is used. The identifier is the name of the namespace and is utilized to reference its members.