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std::ranges::subrange<I,S,K>::size

From cppreference.com
< cpp‎ | ranges‎ | subrange
 
 
Ranges library
 
 
constexpr /*make-unsigned-like-t*/<std::iter_difference_t <I>> size() const
    requires (K == ranges::subrange_kind::sized);
(since C++20)

Obtains the number of elements in the subrange:

For the definition of /*make-unsigned-like-t*/, see make-unsigned-like-t  .

[edit] Return value

As described above.

[edit] Example

Run this code
#include <functional>
#include <iostream>
#include <ranges>
#include <utility>
 
int main()
{
 const auto v = {2, 2, 2, 7, 1, 1, 1, 1, 8, 2, 2, 2, 2, 2};
 
 // the value type of views::chunk_by is the ranges::subrange
 
 auto to_pair = [](auto sub) { return std::make_pair (sub[0], sub.size()); };
 /* ^^^^ */
 auto pairs = v | std::views::chunk_by (std::equal_to {})
 | std::views::transform (to_pair);
 
 for (auto x : pairs bitor std::views::keys )
 std::cout << x << ' ';
 std::cout << '\n';
 for (auto x : pairs bitor std::views::values )
 std::cout << x << ' ';
 std::cout << '\n';
}

Output:

2 7 1 8 2
3 1 4 1 5

[edit] See also

checks whether the subrange is empty
(public member function) [edit]
(C++17)(C++20)
returns the size of a container or array
(function template) [edit]
returns an integer equal to the size of a range
(customization point object)[edit]
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