如何修复浮点异常：C 代码中的 8

Question

I'm trying to write a program that lists all prime numbers in a given parameter. My terminal won't output anything, even though I have a print function at the end of the program.

Could you also let me know if the x and g variables were necessary or could I have just stuck with i.

Here's my code:

#include <stdio.h>

#define MAX_SIZE 1000
int main(){

    int N , i, x, g, a[MAX_SIZE];

    scanf("%d", &N);

    a[0] = 2;

    for (i = 1; i < N - 2; i++)
    {
        a[i] = (a[i-1]) + 1;
    }

    for (x = 0; x < N - 2; x++){
        for (i = 1; i < N - 2; i++){
            if (a[i] % a[x] == 0) {
                for (g = i; g < N - 2; g++){
                    a[g] = a[g+1];
                }
            }
        }
    }


    for (i = 0; i < N - 2; i++){
        printf("%d \n", a[i]);
    }

   return 0;
}

Answer 1

You have off-by-one error here:

for (g = i; g < N - 2; g++){
  a[g] = a[g+1];

}

When g = N - 2 - 1 , the value a[N - 2] is used, but the element is not initialized and the value is indeterminate.

You should check and fix your algorithm not to read uninitialized element.

---

Your code looks too complicated for me. Here is an example of my code to print all prime numbers that are N or less:

#include <stdio.h>
#include <stdlib.h>

int main(void) {
    int N;
    int* primes;
    int prime_count;
    int i, j;
    if (scanf("%d", &N) != 1) return 1;
    primes = malloc(sizeof(*primes) * N);
    if (primes == NULL) return 2;

    prime_count = 0;
    for (i = 2; i <= N; i++) {
        int is_prime = 1;
        for (j = 0; j < prime_count; j++) {
            if (i % primes[j] == 0) {
                is_prime = 0;
                break;
            }
        }
        if (is_prime) primes[prime_count++] = i;
    }

    for (i = 0; i < prime_count; i++) {
        printf("%d\n", primes[i]);
    }

    free(primes);
    return 0;
}