题解 | #ASCII码#

import java.util.Scanner;
public class Main{
    public static void main(String[]args){
        Scanner input=new Scanner(System.in);
        double a=input.nextDouble();
        double b=input.nextDouble();
        double c=input.nextDouble();
        double C=a+b+c;
        double S=Math.pow((C/2)*(C/2-a)*(C/2-b)*(C/2-c),0.5);//海伦公式
        System.out.println("circumference="+String.format("%.2f",C)+" "+"area="+String.format("%.2f",S));
    }
}