C语言求质数和各项累加值

Question

希望出现的结果是：
输出两列，一列是质数，另一列是累加值。
如下：
2 2
3 5
5 10
7 17
9 26
……

Answer 1

#include <stdio.h>

// Returns 1 if x is a prime, otherwise returns 0.
int is_prime(unsigned int x) {
  if (x < 2)
    return 0;
  for (int i = 2; i * i <= x; i++) {
    if (x % i == 0)
      return 0;
  }
  return 1;
}

// Restores the last calculated prime and sum from EEPROM.
void restore(unsigned int *A, unsigned int *sum) {
  // ...
}

// Saves the calculated prime and sum to EEPROM for resuming the calculation
// later.
void save(unsigned int A, unsigned int sum) {
  // ...
}

// Shows LED for the specified period in ms.
void showLed(unsigned int ms) {
  // ...
}

int main() {
  unsigned int A = 0, sum = 0, n = 0, i = 0;
  restore(&A, &sum); // Restore the last A and sum from EEPROM
  while (++i > 0) {
    if (is_prime(i)) {
      A = i;
      if (sum + i < sum) {
        printf("overflow, stop\n");
        break;
      }
      sum += i;
      printf("%u %u\n", i, sum);
      if (++n % 10 == 0)
        showLed(2000); // Show LED for 2 seconds
      save(A, sum);    // Save current A and sum to EEPROM
    }
  }
  return 0;
}