[delta_p_delta_x]

There's a nicer way still:

    #include <algorithm>
    #include <functional>
    #include <iostream>
    #include <numeric>
    #include <ranges>
    #include <vector>

    int main() 
    {
        std::vector<int> vec{1, 2, 3, 4, 5};
        auto plus_one{[](const auto x) { return x + 1; }};
        std::ranges::for_each(vec | std::views::transform(plus_one), [](const auto x) {
            std::cout << x << " ";
        });
        std::cout << "\n";

        std::cout << std::accumulate(std::begin(vec), std::end(vec), 1, std::multiplies<>()) << "\n";

        return 0;
    }

https://godbolt.org/z/84ePjfPhf