public static void main(String[] args) {
Scanner in =new Scanner(System.in);
System.out.println("请输入一个正整数回车结束");
int num=in.nextInt();
int count=0;
for(int i=1;i<=num;i++){
if(num%i==0){
count++;
}
}
if(count==2)
System.out.println(num+"是素数");
}