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

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;
}

THE LENGTH OF THIS STRING IS 42 CHARACTERS

See also