std::ranges::views::cartesian_product,std::ranges::cartesian_product_view

From cppreference.com

Compiler support
Freestanding and hosted
Language
Standard library
Standard library headers
Named requirements
Feature test macros(C++20)
Language support library
Concepts library(C++20)
Diagnostics library
Memory management library
Metaprogramming library(C++11)
General utilities library
Containers library
Iterators library
Ranges library(C++20)
Algorithms library
Strings library
Text processing library
Numerics library
Date and time library
Input/output library
Filesystem library(C++17)
Concurrency support library(C++11)
Execution control library(C++26)
Technical specifications
Symbols index
External libraries

[edit]

Ranges library

Range access

begin
cbegin
end
cend

rbegin
crbegin
rend
crend

size
ssize
data
cdata

reserve_hint (C++26)
empty

Range conversions
std::from_range_t std::from_range (C++23)(C++23)
to (C++23)

Dangling iterator handling
dangling
borrowed_iterator_t
borrowed_subrange_t

Range primitives

range_size_trange_difference_trange_value_t
elements_of (C++23)

iterator_tconst_iterator_tsentinel_tconst_sentinel_t

(C++23)(C++23)

range_reference_trange_const_reference_trange_rvalue_reference_trange_common_reference_t

(C++23)

Range concepts

range
borrowed_range
common_range

sized_range
viewable_range
view

input_range
output_range
forward_range

bidirectional_range
random_access_range
contiguous_range

approximately_sized_range (C++26)
constant_range (C++23)

empty_viewviews::empty

single_viewviews::single

basic_istream_viewviews::istream

iota_viewviews::iota

repeat_viewviews::repeat

(C++23)(C++23)

Range adaptors

views::all_tviews::all
as_rvalue_viewviews::as_rvalue (C++23)(C++23)
filter_viewviews::filter
transform_viewviews::transform
take_viewviews::take
take_while_viewviews::take_while
common_viewviews::common
views::counted
to_input_viewviews::to_input (C++26)(C++26)

ref_view
drop_viewviews::drop
drop_while_viewviews::drop_while
lazy_split_viewviews::lazy_split
split_viewviews::split
join_viewviews::join
join_with_viewviews::join_with (C++23)(C++23)
concat_viewviews::concat (C++26)(C++26)
cache_latest_viewviews::cache_latest (C++26)(C++26)

owning_view
reverse_viewviews::reverse
as_const_viewviews::as_const (C++23)(C++23)
elements_viewviews::elements
keys_viewviews::keys
values_viewviews::values
enumerate_viewviews::enumerate (C++23)(C++23)
zip_viewviews::zip (C++23)(C++23)
zip_transform_viewviews::zip_transform (C++23)(C++23)

adjacent_viewviews::adjacent (C++23)(C++23)
views::pairwise (C++23)
adjacent_transform_viewviews::adjacent_transform (C++23)(C++23)
views::pairwise_transform (C++23)
chunk_viewviews::chunk (C++23)(C++23)
slide_viewviews::slide (C++23)(C++23)
chunk_by_viewviews::chunk_by (C++23)(C++23)
stride_viewviews::stride (C++23)(C++23)
cartesian_product_viewviews::cartesian_product (C++23)(C++23)

Range generators
std::generator (C++23)

Range adaptor closure objects
range_adaptor_closure (C++23)

Range adaptor objects

Helper items

copyable-box
movable-box

(until C++23) (C++23)

simple-view
non-propagating-cache

[edit]

std::ranges::cartesian_product_view

Member functions
cartesian_product_view::cartesian_product_view
cartesian_product_view::begin
cartesian_product_view::end
cartesian_product_view::size
Deduction guides
Iterator
Member functions
cartesian_product_view::iterator::iterator
cartesian_product_view::iterator::operator*
cartesian_product_view::iterator::operator[]
cartesian_product_view::iterator::operator++ cartesian_product_view::iterator::operator++(int) cartesian_product_view::iterator::operator-- cartesian_product_view::iterator::operator--(int) cartesian_product_view::iterator::operator+= cartesian_product_view::iterator::operator-=
cartesian_product_view::iterator::next
cartesian_product_view::iterator::prev
cartesian_product_view::iterator::distance_from
Non-member functions
operator==(cartesian_product_view::iterator) operator<=>(cartesian_product_view::iterator)
operator+(cartesian_product_view::iterator) operator-(cartesian_product_view::iterator)
iter_move(cartesian_product_view::iterator)
iter_swap(cartesian_product_view::iterator)

[edit]

Defined in header`<ranges>`
template<ranges::input_range First,ranges::forward_range...Vs> requires(ranges::view<First>&& ...&&ranges::view<Vs>) class cartesian_product_view :publicranges::view_interface<cartesian_product_view<First, Vs...>>	(1)	(since C++23)
namespace views{ inlineconstexpr/unspecified/ cartesian_product=/unspecified/; }	(2)	(since C++23)
Call signature
template<ranges::viewable_range...Rs> requires/* see below */ constexprranges::viewauto cartesian_product( Rs&&...rs);		(since C++23)
Helper concepts
template<bool Const,class First,class...Vs> concept/cartesian-product-is-random-access/= (ranges::random_access_range</maybe-const/<Const, First>>&& ...&& (ranges::random_access_range</maybe-const/<Const, Vs>>&& ranges::sized_range</maybe-const/<Const, Vs>>));	(3)	(exposition only*)
template<class R> concept/cartesian-product-common-arg/= ranges::common_range<R>\|\| (ranges::sized_range<R>&&ranges::random_access_range<R>);	(4)	(exposition only*)
template<bool Const,class First,class...Vs> concept/cartesian-product-is-bidirectional/= (ranges::bidirectional_range</maybe-const/<Const, First>>&& ...&& (ranges::bidirectional_range</maybe-const/<Const, Vs>>&& /cartesian-product-common-arg/</maybe-const/<Const, Vs>>));	(5)	(exposition only*)
template<class First,class...Vs> concept/cartesian-product-is-common/= /cartesian-product-common-arg/<First>;	(6)	(exposition only*)
template<class...Vs> concept/cartesian-product-is-sized/= (ranges::sized_range<Vs>&& ...);	(7)	(exposition only*)
template<bool Const,template<class>class FirstSent,class First,class...Vs> concept/cartesian-is-sized-sentinel/= (std::sized_sentinel_for<FirstSent</maybe-const/<Const, First>>, ranges::iterator_t</maybe-const/<Const, First>>>&& ...&& (ranges::sized_range</maybe-const/<Const, Vs>>&& std::sized_sentinel_for<ranges::iterator_t< /maybe-const/<Const, Vs>>, ranges::iterator_t</maybe-const/<Const, Vs>>>));	(8)	(exposition only*)
Helper function templates
template</cartesian-product-common-arg/ R> constexprauto/cartesian-common-arg-end/( R& r) { ifconstexpr(ranges::common_range<R>) returnranges::end(r); else returnranges::begin(r)+ranges::distance(r); }	(9)	(exposition only*)

1)cartesian_product_view is a range adaptor that takesnviews, wheren > 0, and produces aview of tuples calculated by then-ary cartesian product of the provided ranges. The size of produced view is a multiple of sizes of provided ranges, while each element is a tuple (of references) of the sizen.

2)views::cartesian_product is a customization point object.

When calling with no argument,views::cartesian_product() isexpression-equivalent toviews::single(std::tuple()).
Otherwise,views::cartesian_product(rs...) isexpression-equivalent toranges::cartesian_product_view<views::all_t<decltype((rs))>...>(rs...).

3) Determines ifcartesian_product is a random access range (see alsorandom_access_range).

4) Determines ifcartesian_product is a common range (see alsocommon_range).

5) Determines ifcartesian_product is a bidirectional range (see alsobidirectional_range).

6) Determines ifcartesian_product satisfies the helper concept/*cartesian-product-is-common*/ (see alsocommon_range).

7) Determines ifcartesian_product is a sized range (see alsosized_range).

8) Determines ifcartesian_product uses sized sentinel.

9) Returns the end of the producedview. Participates in overload resolution only ifcartesian_product satisfies the helper concept/*cartesian-product-common-arg*/.

TheFirstrange passed tocartesian_product_view is treated specially, since it is only passed through a single time. As a result, several constrains are relaxed on it:

First is aninput_range instead offorward_range;
First does not have to be asized_range in order for thecartesian_product_view to berandom_access_range orcommon_range;
First does not have to becommon_range in order for thecartesian_product_view to bebidirectional_range.

Customization point objects

The nameviews::cartesian_product denotes acustomization point object, which is a constfunction object of aliteral semiregular class type. SeeCustomizationPointObject for details.

[edit]Data members

Member	Definition
std::tuple<First, Vs...>`base_`(private)	An object that holds all adapted`view` objects. (exposition-only member object*)

[edit]Member functions

(constructor)	constructs a`cartesian_product_view` (public member function)[edit]
begin	returns an iterator to the beginning (public member function)[edit]
end	returns an iterator or a sentinel to the end (public member function)[edit]
size	returns the number of elements, provided only if the underlying (adapted) range satisfies`sized_range` (public member function)[edit]
Inherited fromstd::ranges::view_interface
empty	returns whether the derived view is empty, provided only if it satisfies`sized_range` or`forward_range` (public member function of`std::ranges::view_interface<D>`)[edit]
cbegin (C++23)	returns a constant iterator to the beginning of the range (public member function of`std::ranges::view_interface<D>`)[edit]
cend (C++23)	returns a sentinel for the constant iterator of the range (public member function of`std::ranges::view_interface<D>`)[edit]
operator bool	returns whether the derived view is not empty, provided only ifranges::empty is applicable to it (public member function of`std::ranges::view_interface<D>`)[edit]
front	returns the first element in the derived view, provided if it satisfies`forward_range` (public member function of`std::ranges::view_interface<D>`)[edit]
back	returns the last element in the derived view, provided only if it satisfies`bidirectional_range` and`common_range` (public member function of`std::ranges::view_interface<D>`)[edit]
operator[]	returns the`n`^th element in the derived view, provided only if it satisfies`random_access_range` (public member function of`std::ranges::view_interface<D>`)[edit]

[edit]Deduction guides

[edit]Nested classes

iterator

the iterator type
(exposition-only member class template*)

[edit]Notes

Feature-test macro	Value	Std	Feature
`__cpp_lib_ranges_cartesian_product`	`202207L`	(C++23)	`std::ranges::cartesian_product_view`

[edit]Example

Run this code

#include <array>#include <iostream>#include <list>#include <ranges>#include <string>#include <vector> void print(std::tuple<charconst&,intconst&,std::stringconst&> t,int pos){constauto&[a, b, c]= t;std::cout<<'('<< a<<' '<< b<<' '<< c<<')'<<(pos%4?" ":"\n");} int main(){constauto x=std::array{'A','B'};constauto y=std::vector{1,2,3};constauto z=std::list<std::string>{"α","β","γ","δ"}; for(int i{1};autoconst& tuple: std::views::cartesian_product(x, y, z))        print(tuple, i++);}

Output:

(A 1 α) (A 1 β) (A 1 γ) (A 1 δ)(A 2 α) (A 2 β) (A 2 γ) (A 2 δ)(A 3 α) (A 3 β) (A 3 γ) (A 3 δ)(B 1 α) (B 1 β) (B 1 γ) (B 1 δ)(B 2 α) (B 2 β) (B 2 γ) (B 2 δ)(B 3 α) (B 3 β) (B 3 γ) (B 3 δ)