operator+(std::reverse_iterator)

Since C++23

Header: <iterator>

Returns the iterator it incremented by n. In fact, the underlying iterator is decremented by n.

# Declarations

template< class Iter >
reverse_iterator<Iter> operator+
( typename reverse_iterator<Iter>::difference_type n,
const reverse_iterator<Iter>& it );

(constexpr since C++17) (until C++23)

template< class Iter >
constexpr reverse_iterator<Iter> operator+
( std::iter_difference_t<Iter> n, const reverse_iterator<Iter>& it );

(since C++23)

# Parameters

n: the number of positions to increment the iterator
it: the iterator adaptor to increment

# Return value

reverse_iterator(it.base() - n)

# Example

#include <iostream>
#include <iterator>
#include <list>
#include <vector>
 
int main()
{
    {
        std::vector v{0, 1, 2, 3};
        std::reverse_iterator<std::vector<int>::iterator>
            ri1{std::reverse_iterator{v.rbegin()}};
        std::cout << *ri1 << ' '; // 3
        std::reverse_iterator<std::vector<int>::iterator> ri2{2 + ri1};
        std::cout << *ri2 << ' '; // 1
    }
 
    {
        std::list l{5, 6, 7, 8};
        std::reverse_iterator<std::list<int>::iterator>
            ri1{std::reverse_iterator{l.rbegin()}};
        std::cout << *ri1 << '\n'; // 8
    //  auto ri2{2 + ri1}; // Error: the underlying iterator does not
                           //        model random access iterator
    }
}