我试了好久了，总是输出有误，求大佬帮忙
public class HelloWorld{
public static void main(String[] args){
int num = 999;
int count = 0;
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("输入有误!");
}
}
}
就是运行成功，输出错误
