哪里错了啊
public class HelloWorld{
public static void main(String[] args){
int num = 999;
int count = 0;
if(num != 0 && num >= 999999999);{
while(num != 0){
num = num / 10;
count++;
}
System.out.println("它是个"+ count + "位的数!");
} else{
System.out.println("输入有误!");
}
}
}