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("它是個"+count+"位的數");
}
else
????System.out.println("輸入有誤！");
}
}