#include bool is_prime(int n) { if (n < 2) { return false; } if (n % 2 == 0) { return n == 2; } if (n % 3 == 0) { return n == 3; } int i = 5; while (i * i <= n) { if (n % i == 0) { return false; } i += 2; if (n % i == 0) { return false; } i += 4; } return true; } int main() { const int start = 1; const int stop = 1000; int sum = 0; int count = 0; int sc = 0; for (int p = start; p < stop; p++) { if (is_prime(p)) { count++; sum += p; if (is_prime(sum)) { printf("The sum of %3d primes in [2, %3d] is %5d which is also prime\n", count, p, sum); sc++; } } } printf("There are %d summerized primes in [%d, %d)\n", sc, start, stop); return 0; }