二重循环语句

package Hello;

public class MyName{
 int num = 999;
 int count = 0;                                  //这行错哪里了
 if(num >= 0 && num <= 999999999){
 while(num != 0){
     count++;
     num /= 10;
 }

     System.out.println("它是个"+count+"位的数");
 }else{
     System.out.println("输入错误");
 }
}
}