密码工程-小素数

代码：

#include <stdio.h>
int main() {
int i,n,x,j,k,q;
scanf("%d",&n);
n=n+1;
while(n>=1048576){
printf("%s","n is too large\n");
scanf("%d",&n);
}
int b[n];
int P[n];
for(x=0;x<n;x++)
{
b[x]=1;
}
i=2;
while(i*i<=n){
for(x=2;x<=(n/i);x++)
{
b[x*i]=0;
}
i=i+1;
}
q=0;
printf("%s","the list:");
for(k=2;k<=n;k++){
 if(b[k]==1){
  printf("%d ",k);
  q=q+1;
 }
}
printf("%s","\n the lenth of list:");
printf("%d",q);
return 0;
}

 

测试截图：