std::ranges::transform_view::size(3)

NAME
std::ranges::transform_view::size - std::ranges::transform_view::size

Synopsis
   constexpr auto size() requires ranges::sized_range<V>; (since C++20)
   constexpr auto size() const requires ranges::sized_range<const V>; (since C++20)
   Returns the number of elements.
   Returns ranges::size(base_), where base_ is the underlying view.

Parameters
   (none)

Return value
   The number of elements.

Notes
   If V does not model forward_range, size() might not be well-defined after a call to
   begin().

Example
// Run this code
 #include <cctype>
 #include <iostream>
 #include <ranges>
 #include <string>
 int main()
 {
     std::string s{"The length of this string is 42 characters"};
     auto tv = std::ranges::transform_view{s, [](char c) -> char
     {
         return std::toupper(c);
     }};
     for (auto x : tv)
         std::cout << x;
     std::cout << "\nsize = " << tv.size() << '\n';
 }

Output:
 THE LENGTH OF THIS STRING IS 42 CHARACTERS
 size = 42

See also
   ranges::size returns an integer equal to the size of a range
   (C++20) (customization point object)
   ranges::ssize returns a signed integer equal to the size of a range
   (C++20) (customization point object)