题解 | #计算三角形的面积和周长#

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        double a = scanner.nextDouble();
        double b = scanner.nextDouble();
        double c = scanner.nextDouble();
        //周长
        double p = a + b + c;
        //海伦面积公式
        double s = (a + b + c) / 2;
        double area = Math.sqrt(s * (s - a) * (s - b) * (s - c));
        System.out.printf("circumference=%.2f area=%.2f", p, area);
    }
}