Day3.

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        // 读取输入的三个点的坐标
        int x1 = scanner.nextInt();
        int y1 = scanner.nextInt();
        int x2 = scanner.nextInt();
        int y2 = scanner.nextInt();
        int x3 = scanner.nextInt();
        int y3 = scanner.nextInt();

        // 计算三条边的长度
        double side1 = Math.sqrt(Math.pow(x2 - x1, 2) + Math.pow(y2 - y1, 2));
        double side2 = Math.sqrt(Math.pow(x3 - x2, 2) + Math.pow(y3 - y2, 2));
        double side3 = Math.sqrt(Math.pow(x1 - x3, 2) + Math.pow(y1 - y3, 2));

        // 判断是否构成三角形
        if (side1 + side2 > side3 && side1 + side3 > side2 && side2 + side3 > side1) {
            // 计算周长
            double perimeter = side1 + side2 + side3;
            // 使用海伦公式计算面积
            double s = perimeter / 2;
            double area = Math.sqrt(s * (s - side1) * (s - side2) * (s - side3));

            System.out.printf("L = %.2f, A = %.2f", perimeter, area);
        } else {
            System.out.println("Impossible");
        }
    }
}
该程序主要功能是根据输入的三个点的坐标计算构成的三角形的周长和面积