std::incrementable - cppreference.com

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

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