题解 | #计算三角形的周长和面积#

import java.util.Scanner;
public class Main{
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        String str = in.nextLine();
		String[] lengths = str.split(" ");
        double circumference = 0;
        double[] length = new double[3];
        for(int i = 0; i < 3; i++) {
            length[i] = Double.parseDouble(lengths[i]);
            circumference += length[i];
        }
        //计算面积用海伦公式
        double p = circumference / 2;
        double area = Math.sqrt(p * (p - length[0]) * (p - length[1]) * (p - length[2]));
        System.out.printf("circumference=%.2f area=%.2f", circumference, area);
    }
}