operator+ (std::reverse_iterator)

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Iterator library
Iterator concepts
Iterator primitives
Algorithm concepts and utilities
Indirect callable concepts
Common algorithm requirements
(C++20)
(C++20)
(C++20)
Utilities
(C++20)
Iterator adaptors
Range access
(C++11) (C++14)
(C++14) (C++14)
(C++11) (C++14)
(C++14) (C++14)
(C++17) (C++20)
(C++17)
(C++17)
Defined in header <iterator>
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)

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

Parameters

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

Return value

reverse_iterator < Iter > ( 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
    }
}

Output:

3 1 8

See also

advances or decrements the iterator
(public member function)
computes the distance between two iterator adaptors
(function template)