std::reverse_iterator

template< class Iter >
class reverse_iterator : public std::iterator<
                           typename std::iterator_traits<Iter>::iterator_category,
                           typename std::iterator_traits<Iter>::value_type,
                           typename std::iterator_traits<Iter>::difference_type,
                           typename std::iterator_traits<Iter>::pointer,
                           typename std::iterator_traits<Iter>::reference >

template< class Iter >
class reverse_iterator;

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 (as long as r is dereferenceable); 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 functions

Member objects

Non-member functions

Notes

std::reverse_iterator does not work with iterators that return a reference to a member object (so-called "stashing iterators"). An example of stashing iterator is std::filesystem::path::iterator.

Example

#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';
}

OlleH

See also