std::incrementable

< cpp‎ | iterator
Defined in header <iterator>
template<class I>

    concept incrementable =
        std::regular<I> &&
        std::weakly_incrementable<I> &&
        requires(I i) {
            { i++ } -> std::same_as<I>;

        };
 (since C++20)

This concept specifies requirements on types that can be incremented with the pre- and post-increment operators, whose increment operations are equality-preserving, and the type is std::equality_comparable.

Unlike with std::weakly_incrementable, which only support single-pass algorithms, multi-pass one-directional algorithms can be used with types that model std::incrementable.

Semantic requirements

I models std::incrementable only if given any two incrementable objects a and b of type I:

  • bool(a == b) implies bool(a++ == b), and
  • bool(a == b) implies bool(((void)a++, a) == ++b)

Equality preservation

Expressions declared in requires-expressions of the standard library concepts are required to be equality-preserving (except where stated otherwise).

See also

(C++20)
 specifies that a semiregular type can be incremented with pre- and post-increment operators
(concept)
(C++20)
 specifies that a type is the same as another type
(concept)