/*
編寫三角形類,實現三角形面積和周長計算等功能。
要求:
(1)三個屬性
(2)兩個構造方法和全部getter和setter
(3)三個自定義的方法:面積、周長、是否是直角三角形。
(4)單獨編寫測試類,測試類的全部功能。
 */

class Triangle{
    //三條邊屬性私有化
    private double edge1;
    private double edge2;
    private double edge3;
//構造方法
    public Triangle() {
    }

    public Triangle(double edge1, double edge2, double edge3) {
        this.edge1 = edge1;
        this.edge2 = edge2;
        this.edge3 = edge3;
    }
    //setter和getter
    public void setEdge1(double edge1) {
        this.edge1 = edge1;
    }

    public void setEdge2(double edge2) {
        this.edge2 = edge2;
    }

    public void setEdge3(double edge3) {
        this.edge3 = edge3;
    }

    public double getEdge1() {
        return edge1;
    }

    public double getEdge2() {
        return edge2;
    }

    public double getEdge3() {
        return edge3;
    }
    /*三條邊求三角形面積
    （海倫公式）（p=(a+b+c)/2）
S=sqrt[p(p-a)(p-b)(p-c)]
     */
   public double area(){
        double p;
        p=(edge1+edge2+edge3)/2;
        return Math.sqrt(p*(p-edge1)*(p-edge2)*(p-edge3));
    }
   public double perimeter (){
       return edge1+edge2+edge3;
   }
   public boolean isRightTriangle(){
       if (Math.pow(edge1,2)+Math.pow(edge2,2)==Math.pow(edge3,2)||Math.pow(edge1,2)+Math.pow(edge3,2)==Math.pow(edge2,2)||Math.pow(edge2,2)+Math.pow(edge3,2)==Math.pow(edge1,2))
           return true;
       return false;
    }
}
public class Text03 {
    public static void main(String[] args) {
        Triangle triangle=new Triangle(3,4,5);
        System.out.println(triangle.isRightTriangle()==true?"是直角三角形":"不是直角三角形");
        System.out.println("面積為："+triangle.area());
        System.out.println("周長為:"+triangle.perimeter());
    }
}