输出1到N之间的素数

#include <stdio.h>#include <math.h>int f(int i){    int j, flag = 0;    for (j=2; j<=sqrt(i); j++)    {        if (i % j == 0)        {            flag = 1;            return 0;        }    }    if (flag == 0)        return i;}int main(){    int i, n, sushu;    scanf("%d", &n);    for (i=2; i<=n; i++)    {        sushu = f(i);        if (sushu != 0)            printf("%d\n", sushu);    }        return 0;}