W3cubDocs

/C++

std::ranges::chunk_view<V>::outer-iterator

class /*outer-iterator*/

(since C++23)

The return type of chunk_view::begin if V models input_range.

The name of this class (shown here as /*outer-iterator*/) is unspecified.

Data members

Typical implementations of /*outer-iterator*/ hold only one non-static data member – a pointer parent_ (the name is for exposition purposes only) to the "parent object", of type ranges::chunk_view*.

Member types

Member type	Definition
`iterator_concept`	`std::input_iterator_tag`
`difference_type`	`ranges::range_difference_t<V>`

Member functions

(constructor) (C++23)	constructs an iterator (public member function)
operator= (C++23)	move assigns another iterator (public member function)
operator* (C++23)	accesses the element (public member function)
operator++ (C++23)	increments the iterator (public member function)

Non-member functions

operator== (C++23)	compares the iterator with default sentinel (function)
operator- (C++23)	calculates the number of chunks remaining (function)

Nested classes

value_type

(C++23)

the value type of /*output-iterator*/
(public member class)

Example

A link to Compiler Explorer.

#include <iostream>
#include <iterator>
#include <sstream>
#include <ranges>
 
int main()
{
    const std::string source{"ABCDEFGHIJ"};
 
    auto letters = std::istringstream{source};
    auto chunks = std::ranges::istream_view<char>(letters)
                | std::views::chunk(4);
 
    for (auto outer_iter = chunks.begin(); outer_iter != std::default_sentinel;
         ++outer_iter)
    {
        auto chunk = *outer_iter; // chunk is an object of type
                                  // chunk_view::outer_iterator::value_type
        std::cout << '[';
        for (auto inner_iter = chunk.begin(); inner_iter != std::default_sentinel;
             ++inner_iter)
            std::cout << *inner_iter;
        std::cout << "] ";
    }
    std::cout << '\n';
 
    // The same output using range-for loops
    auto letters2 = std::istringstream{source};
    auto chunks2 = std::ranges::istream_view<char>(letters2)
                 | std::views::chunk(4);
    for (auto chunk : chunks2)
    {
        std::cout << '[';
        for (auto ch : chunk)
            std::cout << ch;
        std::cout << "] ";
    }
    std::cout << '\n';
}

Output:

[ABCD] [EFGH] [IJ]
[ABCD] [EFGH] [IJ]

References

C++23 standard (ISO/IEC 14882:2023):

26.7.28.3 Class chunk_view::outer-iterator [range.chunk.outer.iter]