public class second
{
    public static void main(String[] args)
    {
          Scanner scanner=new Scanner(System.in);
          System.out.println("Please input a number:");
          int i=scanner.nextInt();
          int sum=1;
          while(i>=1)
          {
             sum=sum*i;
             i--;
          }
          System.out.printf("%d 的阶乘为:%d",scanner.nextInt(),sum);
     }
}
他总是提示Scanner那出错,不知道是版本问题,还是怎么回事?帮忙回答一下,我是新手