public?class?HelloWorld{
public?static?void?main(String[]?args){
int?num?=?999;
int?count?=?0;
if(0<=num&&num<=999999999){
????????while(num!=0){
?????????count++;
?????????num/=10;
?????}
?????System.out.println("它是個"+count+"位的數!");
?}
?else{
????System.out.println("錯誤");?
?}
}
}