Iterator library
Iterator concepts
Iterator primitives
Algorithm concepts and utilities
Indirect callable concepts
Common algorithm requirements
Iterator adaptors
Stream iterators
Iterator customization points
Iterator operations
Range access
friend constexpr counted_iterator operator+(

  std::iter_difference_t<I> n, const counted_iterator& x )

    requires std::random_access_iterator<I>;
(since C++20)

Returns an iterator adaptor which is advanced by n. The behavior is undefined if n is greater than the length recorded within x (i.e. if x + n result in undefined behavior).

This function is not visible to ordinary unqualified or qualified lookup, and can only be found by argument-dependent lookup when std::counted_iterator<I> is an associated class of the arguments.


[edit] Parameters

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

[edit] Return value

An iterator adaptor equal to x + n.

[edit] Example

#include <iostream>
#include <iterator>
#include <list>
#include <vector>
int main()
    std::vector v { 0, 1, 2, 3, 4, 5 };
    std::counted_iterator<std::vector<int>::iterator> p{ v.begin() + 1, 4 };
    std::cout << "*p:" << *p << ", count:" << p.count() << '\n';
    std::counted_iterator<std::vector<int>::iterator> q{ 2 + p };
    std::cout << "*q:" << *q << ", count:" << q.count() << '\n';
    std::list l { 6, 7, 8, 9 };
    std::counted_iterator<std::list<int>::iterator> r{ l.begin(), 3 };
    std::cout << "*r:" << *r << ", count:" << r.count() << '\n';
//  auto s { 2 + r }; // error: the underlying iterator does
                      // not model std::random_access_iterator


*p:1, count:4
*q:3, count:2
*r:6, count:3

[edit] See also

advances or decrements the iterator
(public member function) [edit]
computes the distance between two iterator adaptors
(function template) [edit]
computes the signed distance to the end
(function template) [edit]