23 Containers library [containers]

23.3 Sequence containers [sequences]

23.3.3 Class template array [array]

23.3.3.5 Zero-sized arrays [array.zero]

array shall provide support for the special case N == 0.
In the case that N == 0, begin() == end() == unique value.
The return value of data() is unspecified.
The effect of calling front() or back() for a zero-sized array is undefined.
Member function swap() shall have a non-throwing exception specification.