//******************************************************** // The following code example is taken from the book // C++20 - The Complete Guide // by Nicolai M. Josuttis (www.josuttis.com) // http://www.cppstd20.com // // The code is licensed under a // Creative Commons Attribution 4.0 International License // http://creativecommons.org/licenses/by/4.0/ //******************************************************** #include #include int main() { auto isPrime = [](int value) constexpr { for (int i = 2; i <= value/2; ++i) { if (value % i == 0) { return false; } } return value > 1; // 0 and 1 are no prime numbers }; // local compile-time computation of Num prime numbers: auto primeNumbers = [isPrime] () consteval { std::array primes; int idx = 0; for (int val = 1; idx < Num; ++val) { if (isPrime(val)) { primes[idx++] = val; } } return primes; }; // init array with prime numbers: auto primes = primeNumbers.operator()<100>(); for (auto v : primes) { std::cout << v << '\n'; } }