cpp-course/modules/14_cpp26/include/constexpr_frontier.hpp

#pragma once

#include <algorithm>
#include <array>

namespace cpp26 {

[[nodiscard]] constexpr auto compile_time_factorial(int n) -> long long {
    auto result = 1LL;
    for (auto i = 2; i <= n; ++i) {
        result *= i;
    }
    return result;
}
[[nodiscard]] constexpr auto compile_time_sum(std::array<int, 5> values) -> int {
    return std::ranges::fold_left(values, 0, std::plus{});
}
[[nodiscard]] constexpr auto is_sorted(const std::array<int, 5> &values) -> bool {
    return std::ranges::is_sorted(values); // also a constexpr function

}

}  // namespace cpp26