std::ranges::transform_view<V,F>:: size

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

#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};
    assert(tv.size() == 42);
    for (auto x : tv)
        std::cout << x;
}

THE LENGTH OF THIS STRING IS 42 CHARACTERS

See also