std::common_iterator<I,S>::common_iterator

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Compiler support
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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)
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Iterator library

Iterator concepts

indirectly_readable (C++20)
indirectly_writable (C++20)
weakly_incrementable (C++20)
incrementable (C++20)
is-integer-like is-signed-integer-like (C++20)(C++20)

sentinel_for (C++20)
sized_sentinel_for (C++20)
input_iterator (C++20)
output_iterator (C++20)
input_or_output_iterator (C++20)

forward_iterator (C++20)
bidirectional_iterator (C++20)
random_access_iterator (C++20)
contiguous_iterator (C++20)

Iterator primitives

input_iterator_tagoutput_iterator_tagforward_iterator_tagbidirectional_iterator_tagrandom_access_iterator_tagcontiguous_iterator_tag

(C++20)

iter_value_titer_difference_titer_reference_titer_const_reference_titer_rvalue_reference_titer_common_reference_t

(C++20)(C++20)(C++20)(C++23)(C++20)(C++20)

iterator (deprecated in C++17)
iterator_traits
incrementable_traits (C++20)
indirectly_readable_traits (C++20)

Algorithm concepts and utilities

Indirect callable concepts

indirectly_unary_invocableindirectly_regular_unary_invocable

(C++20)(C++20)

indirect_unary_predicate (C++20)
indirect_binary_predicate (C++20)

indirect_equivalence_relation (C++20)
indirect_strict_weak_order (C++20)

Common algorithm requirements

indirectly_movable (C++20)
indirectly_movable_storable (C++20)
indirectly_copyable (C++20)

indirectly_copyable_storable (C++20)
indirectly_swappable (C++20)
indirectly_comparable (C++20)

permutable (C++20)
mergeable (C++20)
sortable (C++20)

(C++20)

(C++20)

(C++26)

reverse_iterator
make_reverse_iterator (C++14)
move_iterator (C++11)
make_move_iterator (C++11)
default_sentinel_tdefault_sentinel (C++20)(C++20)
unreachable_sentinel_tunreachable_sentinel (C++20)(C++20)

front_insert_iterator
back_insert_iterator
inserter
insert_iterator
front_inserter
back_inserter
move_sentinel (C++20)

common_iterator (C++20)
counted_iterator (C++20)
basic_const_iterator (C++23)
const_iterator (C++23)
const_sentinel (C++23)
make_const_iterator (C++23)
make_const_sentinel (C++23)

Stream iterators

istream_iterator
ostream_iterator

istreambuf_iterator
ostreambuf_iterator

Iterator customization points
ranges::iter_move (C++20)
ranges::iter_swap (C++20)

Iterator operations

advance
distance
prev (C++11)
next (C++11)

ranges::advance (C++20)
ranges::distance (C++20)
ranges::prev (C++20)
ranges::next (C++20)

Range access

begincbegin (C++11)(C++14)
rbegincrbegin (C++14)(C++14)

endcend (C++11)(C++14)
rendcrend (C++14)(C++14)

sizessize (C++17)(C++20)
empty (C++17)
data (C++17)

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std::common_iterator

Member functions
common_iterator::common_iterator
common_iterator::operator=
common_iterator::operator*common_iterator::operator->
common_iterator::operator++common_iterator::operator++(int)
Non-member functions
operator== (C++20)
operator- (C++20)
iter_move (C++20)
iter_swap (C++20)
Helper classes
incrementable_traits<std::common_iterator> (C++20)
iterator_traits<std::common_iterator> (C++20)

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constexpr common_iterator() requiresstd::default_initializable<I>=default;	(1)	(since C++20)
constexpr common_iterator( I i);	(2)	(since C++20)
constexpr common_iterator( S s);	(3)	(since C++20)
template<class I2,class S2> requiresstd::convertible_to<const I2&, I>&& std::convertible_to<const S2&, S> constexpr common_iterator(const common_iterator<I2, S2>& x);	(4)	(since C++20)

Constructs a new iterator adaptor, effectively initializes the underlyingstd::variant<I, S> member objectvar to hold anI (iterator) orS (sentinel) object.

1) Default constructor. Default-initializesvar. After construction,var holds a value-initializedI object.Operations on the resulting iterator adaptor have defined behavior if and only if the corresponding operations on a value-initializedI also have defined behavior.

2) After construction,var holds anI object move-constructed fromi.

3) After construction,var holds anS object move-constructed froms.

4) After construction,var holds anI orS object initialized from theI2 orS2 held byx.var, ifx.var holds that alternative, respectively. The behavior is undefined ifx is in an invalid state, that is,x.var.valueless_by_exception() is equal totrue.

[edit]Parameters

i	-	iterator to adapt
s	-	sentinel to adapt
x	-	iterator adaptor to copy

[edit]Example

Run this code

#include <algorithm>#include <iostream>#include <iterator>#include <numeric>#include <vector> int main(){std::vector v{3,1,4,1,5,9,2}; using CI=std::common_iterator<std::counted_iterator<std::vector<int>::iterator>,std::default_sentinel_t>;    CI unused;// (1)    CI start{std::counted_iterator{std::next(begin(v)), ssize(v)-2}};// (2)    CI finish{std::default_sentinel};// (3)    CI first{start};// (4)    CI last{finish};// (4) std::copy(first, last,std::ostream_iterator<int>{std::cout," "});std::cout<<'\n'; std::common_iterator<std::counted_iterator<std::ostream_iterator<double>>,std::default_sentinel_t>            beg{std::counted_iterator{std::ostream_iterator<double>{std::cout,";  "},5}},            end{std::default_sentinel};std::iota(beg, end,3.1);std::cout<<'\n';}