题目坑点,看这里
题目要输入的是实数,不是int类型的整数!!!!
double !!
import java.text.DecimalFormat; import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner sc =new Scanner(System.in); DecimalFormat df = new DecimalFormat("0.000000"); double a=sc.nextDouble(); double pi=3.14159; double s=2*a*pi; double s1=a*a*pi; System.out.println(df.format(s)); System.out.println(df.format(s1)); } }