#include <array>
#include <concepts>
#include <iostream>
#include <span>

template<std::integral T>
long long total(std::span<const T> values) {
    long long sum{0};
    for (T value : values) {
        sum += value;
    }
    return sum;
}

int main() {
    const std::array<int, 5> data{3, 1, 4, 1, 5};
    const std::span<const int> view{data};
    std::cout << total(view) << '\n';
    const std::span<const int> empty{};
    std::cout << total(empty) << '\n';
    return 0;
}