std::reverse_iterator<Iter>::reverse_iterator

 

C++

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

 

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)
Utilities
indirect_result_t (C++20)	projected (C++20)	projected_value_t (C++26)
Iterator adaptors
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)

 

std::reverse_iterator

Member functions

reverse_iterator::reverse_iterator

reverse_iterator::operator=

reverse_iterator::base

reverse_iterator::operator*reverse_iterator::operator->

reverse_iterator::operator[]

reverse_iterator::operator++reverse_iterator::operator+reverse_iterator::operator+=reverse_iterator::operator--reverse_iterator::operator-reverse_iterator::operator-=

Non-member functions

operator==operator!=operator<operator<=operator>operator>=operator<=> (C++20)

operator+

operator-

iter_move (C++20)

iter_swap (C++20)

make_reverse_iterator (C++14)

 

reverse_iterator();	(1)	(constexpr since C++17)
explicit reverse_iterator( iterator_type x );	(2)	(constexpr since C++17)
template< class U > reverse_iterator( const reverse_iterator<U>& other );	(3)	(constexpr since C++17)

Constructs a new reverse_iterator.

Overload	current
(1)	value-initialized
(2)	initialized with x
(3)	initialized with other.current

3) The converting constructor.

This overload participates in overload resolution only if std::is_same_v<U, Iter> is false and std::convertible_to<const U&, Iter> is modeled.

(since C++20)

Parameters

x	-	iterator to adapt
other	-	iterator adaptor to copy

Example

Run this code

#include <cassert>
#include <concepts>
#include <iterator>
#include <vector>
 
int main()
{
    std::vector v{0, 1, 2, 3, 4};
 
    using ReverseIt = std::reverse_iterator<std::vector<int>::const_iterator>;
 
    ReverseIt i1; / overload (1)
    i1 = v.crbegin();
    assert(*i1 == 4);
 
    ReverseIt i2(i1); / overload (2)
    assert(i2[0] == 4);
 
    int x[]{1, 2, 3};
    auto i3 = std::reverse_iterator<int*>(x + std::size(x)); / overload (1)
    i3[0] = -3;
    assert(x[2] == -3);
    std::reverse_iterator<int const*> i4(i3); / overload (3): int => const int
    static_assert(std::convertible_to<decltype(i3)::value_type,
                                      decltype(i4)::value_type>);
    / i4[0] = 5; / Error: assignment of read-only location
}

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR	Applied to	Behavior as published	Correct behavior
LWG 235	C++98	the effect of overload (1) was not specified	specified
LWG 1012	C++98	overload (1) default-initialized current	it is value-initialized
LWG 3435	C++20	overload (3) was not constrained	constrained

See also

operator=	assigns another reverse_iterator (public member function)
make_reverse_iterator (C++14)	creates a std::reverse_iterator of type inferred from the argument (function template)

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