25 Ranges library [ranges]

Ranges are an abstraction that allows a C++ program to operate on elements of data structures uniformly.

Calling ranges​::​begin on a range returns an object whose type models input_or_output_iterator ([iterator.concept.iterator]).

Calling ranges​::​end on a range returns an object whose type S, together with the type I of the object returned by ranges​::​begin, models sentinel_for<S, I>.

The library formalizes the interfaces, semantics, and complexity of ranges to enable algorithms and range adaptors that work efficiently on different types of sequences.

The range concept requires that ranges​::​begin and ranges​::​end return an iterator and a sentinel, respectively.

The sized_range concept refines range with the requirement that ranges​::​size be amortized $O\left(1\right)$.

The view concept specifies requirements on a range type to provide operations with predictable complexity.

Several refinements of range group requirements that arise frequently in concepts and algorithms.

Common ranges are ranges for which ranges​::​begin and ranges​::​end return objects of the same type.

Random access ranges are ranges for which ranges​::​begin returns a type that models random_access_iterator ([iterator.concept.random.access]).

(Contiguous, bidirectional, forward, input, and output ranges are defined similarly.)

Viewable ranges can be converted to views.