cpp/experimental/basic string view/basic string view

@1@ Default constructor. Constructs an empty. @2@ Copy constructor. Constructs a view of the same content as. @3@ Constructs a view of the first characters of the character array starting with the element pointed by. @4@ Constructs a view of the first characters of the character array starting with the element pointed by. can contain null characters. The behavior is undefined if is not a valid range (even though the constructor may not access any of the elements of this range) @5@ Constructs a view of the null-terminated character string pointed to by, not including the terminating null character. The length of the view is determined as if by. The behavior is undefined if is not a valid range (even though the constructor may not access any of the elements of this range)

Exceptions
@4-5@ Throws nothing.

Complexity
@1-4@ constant @5@ linear in length of