C语言判断素数代码

#include<stdio.h>
long long a[9999999] = {0};
void prime(int n)
{
for(int i = 2;i*i <= n;i++)
if(n % i == 0)
return;
a
= 1;
return;
}
int main(int argc,char **argv)
{
a[2] = 1;
for(int i=3;i<=9999999;i++)
prime(i);
for(int j = 2;j<=9999999;j++)
{
printf("%d:",j);
if(a[j] == 1)
printf("是\n");
else
printf("否\n");
}
return 0;
}