std::ranges::transform_view<V,F>::size
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_).
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
#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
See also
|
(C++20) | returns an integer equal to the size of a range (customization point object) |
|
(C++20) | returns a signed integer equal to the size of a range (customization point object) |
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