std::reverse_iterator

 

C++

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Standard library headers

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Utilities library

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Iterators library

Numerics library

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Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

 

Iterator library

Iterator primitives
iterator_traits
input_iterator_tag output_iterator_tag forward_iterator_tag bidirectional_iterator_tag random_access_iterator_tag
iterator
Iterator adaptors
reverse_iterator
move_iterator (C++11) back_insert_iterator front_insert_iterator insert_iterator	make_move_iterator (C++11) back_inserter front_inserter inserter
Stream iterators
istream_iterator
ostream_iterator
istreambuf_iterator
ostreambuf_iterator
Iterator operations
advance
distance
prev (C++11)
next (C++11)
Range access
begin (C++11)
end (C++11)

 

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-

 

Defined in header <iterator>
template< class Iterator > class reverse_iterator : public std::iterator<                            typename std::iterator_traits<Iterator>::iterator_category,                            typename std::iterator_traits<Iterator>::value_type,                            typename std::iterator_traits<Iterator>::difference_type,                            typename std::iterator_traits<Iterator>::pointer,                            typename std::iterator_traits<Iterator>::reference >

std::reverse_iterator is an iterator adaptor that reverses the direction of a given iterator. In other words, when provided with a bidirectional iterator, std::reverse_iterator produces a new iterator that moves from the end to the beginning of the sequence defined by the underlying bidirectional iterator.

For a reverse iterator r constructed from an iterator i, the relationship &*r == &*(i-1) is always true; thus a reverse iterator constructed from a one-past-the-end iterator dereferences to the last element in a sequence.

This is the iterator returned by member functions rbegin() and rend() of the standard library containers.

Member types

Member type	Definition
iterator_type	Iterator
difference_type	std::iterator_traits<Iterator>::difference_type
pointer	std::iterator_traits<Iterator>::pointer
reference	std::iterator_traits<Iterator>::reference

Member functions

(constructor)	constructs a new iterator adaptor (public member function)
operator=	assigns another iterator (public member function)
base	accesses the underlying iterator (public member function)
operator* operator->	accesses the pointed-to element (public member function)
operator[]	obtains rvalue reference to indexed element (public member function)
operator++ operator++(int) operator+= operator+ operator-- operator--(int) operator-= operator-	advances or decrements the iterator (public member function)

Member objects

Member name	Definition
current (protected)	a copy of the base() iterator

In addition to the current value of the underlying iterator, a typical implementation of std::reverse_iterator holds a decremented copy of the underlying iterator, which is used in dereferencing.

Non-member functions

operator== operator!= operator< operator<= operator> operator>=	compares the underlying iterators (function template)
operator+	advances the iterator (function template)
operator-	computes the distance between two iterator adaptors (function template)

Inherited from std::iterator

Member types

Member type	Definition
value_type	std::iterator_traits<Iterator>::value_type
difference_type	std::iterator_traits<Iterator>::difference_type
pointer	std::iterator_traits<Iterator>::pointer
reference	std::iterator_traits<Iterator>::reference
iterator_category	std::iterator_traits<Iterator>::iterator_category

Example

run this code

#include <iostream>
#include <string>
#include <iterator>
 
int main()
{
    std::string s = "Hello, world";
    std::reverse_iterator<std::string::iterator> r = s.rbegin();
    r[7] = 'O'; // replaces 'o' with 'O' 
    r += 7; // iterator now points at 'O'
    std::string rev(r, s.rend());
    std::cout << rev << '\n';
}

Output:

OlleH

See also

iterator	the basic iterator (class template)