Making The Road Wiki

/* P.18 */
void sieve_of_Eratosthenes(int N = 1000) {
  int i, j; bool a[N+1];
  for (a[1] = false, i = 2; i <= N; i++) a[i] = true;
  for (i = 2; i <= N/2; i++)
    for (j = 2; j <= N/i; j++) a[i*j] = false;
  for (i = 1; i <= N; i++)
    if (a[i]) std::cout << i << " ";
  std::cout << std::endl;
}