std::ranges::transform_view<V,F>::size
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std::ranges::transform_view
transform_view::size
(C++26)
constexpr auto size() requires ranges::sized_range <V>;
(1)
(since C++20)
constexpr auto size() const requires ranges::sized_range <const V>;
(2)
(since C++20)
Returns the number of elements. Equivalent to ranges::size (base_ ).
Contents
[edit] Return value
The number of elements.
[edit] Notes
If V does not model forward_range, size() might not be well-defined after a call to begin().
[edit] Example
Run this code
#include <cassert> #include <cctype> #include <iostream> #include <ranges> #include <string> int main() { std::string s{"The length of this string is 42 characters"}; auto to_upper{[](unsigned char c) -> char { return std::toupper (c); }}; auto tv{std::ranges::transform_view {s, to_upper}}; for (assert (tv.size() == 42); const auto c : tv) std::cout << c; }
Output:
THE LENGTH OF THIS STRING IS 42 CHARACTERS