std::ranges::subrange

 

C++

Language

Standard Library Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

 

Ranges library

Range access
begincbegin endcend	rbegincrbegin rendcrend	size empty datacdata
Range primitives
iterator_tsentinel_t	range_difference_trange_value_t	range_reference_trange_rvalue_reference_t
Dangling iterator handling
dangling	borrowed_iterator_t	borrowed_subrange_t
Range concepts
range borrowed_range sized_range	common_range view viewable_range	input_range output_range forward_range	bidirectional_range random_access_range contiguous_range
Views
view_interface	subrange
Semiregular wrapper
Factories
empty_viewviews::empty	single_viewviews::single	iota_viewviews::iota	views::counted
Adaptors
all_viewviews::all join_viewviews::join take_viewviews::take basic_istream_viewistream_view	ref_view                                split_viewviews::split take_while_viewviews::take_while elements_viewviews::elements	common_viewviews::common transform_viewviews::transform drop_viewviews::drop keys_viewviews::keys	reverse_viewviews::reverse filter_viewviews::filter drop_while_viewviews::drop_while values_viewviews::values

 

Defined in header <ranges>
template<   std::input_or_output_iterator I,   std::sentinel_for<I> S = I,   ranges::subrange_kind K = std::sized_sentinel_for<S, I> ?     ranges::subrange_kind::sized : ranges::subrange_kind::unsized >   requires (K == ranges::subrange_kind::sized || !std::sized_sentinel_for<S, I>) class subrange : public ranges::view_interface<subrange<I, S, K>>		(since C++20)

The subrange class template combines together an iterator and a sentinel into a single view.

Additionally, the subrange is a sized_range whenever the final template parameter is subrange_kind​::​sized (which happens when sized_sentinel_for<S, I> is satisfied or when size is passed explicitly as a constructor argument)

Helper template

template<std::input_or_output_iterator I, std::sentinel_for<I> S          ranges::subrange_kind K> inline constexpr bool enable_borrowed_range<ranges::subrange<I, S, K>> = true;

This specialization of std::ranges::enable_borrowed_range makes subrange satisfy borrowed_range.

Example

Run this code

#include <ranges>
 
void mutate_map_values(std::multimap<K,V>& m, K k) {
    using namespace std::ranges;
    for (auto& [_, v] : subrange(m.equal_range(k))) {
        mutate(v);
    }
}