请问一下这个程序哪里有问题?
public class HelloWorld{
public static void main(String[] args){
int num = 999;
int count = 0;
for(;num>0;num--){
if( num%1000000000==1){
System.out.println("它是个10位数!");
break;
}if(num%100000000==1){
System.out.println("它是个9位数!");
break;
}if(num%10000000==1){
System.out.println("它是个8位数!");
break;
}if(num%1000000==1){
System.out.println("它是个7位数!");
break;
}if(num%100000==1){
System.out.println("它是个6位数!");
break;
}if(num%10000==1){
System.out.println("它是个5位数!");
break;
}if(num%1000==1){
System.out.println("它是个4位数!");
break;
}if(num%100==1){
System.out.println("它是个3位数!");
break;
}if(num%10==1){
System.out.println("它是个2位数!");
break;
}if(num%1==1){
System.out.println("它是个1位数!");
break;
}
}
}
}
