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!");
}
}原题中的if输出语句中有“!”,所以对应的验证,你在输出语句里加上试试~~
num应该float吧