Difference between revisions of "cpp/iterator/weakly incrementable"

Revision as of 22:22, 18 September 2020

where /*is-signed-integer-like*/<I> is true if std::signed_integral<I> is true or if I is a class that behaves like a signed integer type including all operators, implicit conversions, and std::numeric_limits specializations.

This concept specifies requirements on types that can be incremented with the pre- and post-increment operators, but those increment operations are not necessarily equality-preserving, and the type itself is not required to be std::equality_comparable.

For std::weakly_incrementable types, a == b does not imply that ++a == ++b. Algorithms on weakly incrementable types must be single-pass algorithms. These algorithms can be used with istreams as the source of the input data through std::istream_iterator.

Semantic requirements

I models std::weakly_incrementable only if given only object i of type I:

• The expressions ++i and i++ have the same domain
• If i is incrementable, then both ++i and i++ advance i
• If i is incrementable, then std::addressof(++i) == std::addressof(i)

See also