The properties of the order of elements are the same as those provided by the underlying containers, as is the validity of more than one active iterators at any one time. Note that changing elements of the container may result in invalidated iterators. Thus, use mutable views only if you really know what you are doing. This is debateable since actually two containers are used.
T has to be assignable.
The type T of the elements accessed through the container. The type of the referenced container. An unsigned integral type. Container Returns an iterator pointing to the begin of the view. Container Returns an iterator pointing to the end of the view.