Valentin Bonnard (Bonnard.V@wanadoo.fr) wrote:

> Proposed resolution:
>
> : -7- **If the container is not empty**, begin() returns an iterator
> : referring to the first element in the
> : container. end() returns an iterator which is the past-the-end value
> : for the container. The container is empty **iff** begin() == end();

Actually, it would be simpler to say:

: -7- end() returns an iterator which is the past-the-end value for the
: container.  If the container is not empty, begin() returns an iterator
: referring to the first element in the container.  If the container is
: empty, then begin() returns the same value as end().

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[First, a note about DR handling: since DR often generate discution
in csc++, I propose that the actual DR should only be sent to issue
list maintainer when such a discution ends (don't tell me that a ng
discution is never required to end), or after a resonable delay. Of
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first.]

Scope: library: container requirements
Type: editorial

While checking where the standard said that begin() == end() implies
empty() (it does in several places), I found the following:

: 23.1 [lib.container.requirements]

: -7- begin() returns an iterator referring to the first element in the
: container. end() returns an iterator which is the past-the-end value
: for the container. If the container is empty, then begin() == end();

If the container is empty, there is no first element for begin()
to refer to !

Proposed resolution:

: -7- **If the container is not empty**, begin() returns an iterator
: referring to the first element in the
: container. end() returns an iterator which is the past-the-end value
: for the container. The container is empty **iff** begin() == end();

Comment about proposed resolution:

  The iff isn't actually required, but it doesn't hurt either
  -- in particular it would help those who don't beleive that
  begin() == end() implies empty().

--

Valentin Bonnard


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