< cpp‎ | iterator
Iterator library
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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.

[edit] 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).

[edit] Equality preservation

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

[edit] See also

specifies that a semiregular type can be incremented with pre- and post-increment operators
(concept) [edit]
specifies that a type is the same as another type
(concept) [edit]