java三角形图形计算器怎么判断边？

public class Test 
{
    public static void main(String[] args) {
        Scanner scan=new Scanner(System.in);
        System.out.println("请输入三角形边长：");
        double a=scan.nextDouble();
        double b=scan.nextDouble();
        double c=scan.nextDouble();
        Triangle s=new Triangle();
        if((a+b)>c&&(a+c)>b&&(b+c)>a){
            s=new Triangle(a,b,c);
            System.out.println("三角形的三边分别为："+a+"\t"+b+"\t"+c);
        }
        else{
            System.out.println("输入的三边不能形成三角形！");
            System.exit(0);
        }
        System.out.println("周长为："+s.round());
        System.out.println("面积为："+s.area());
    }
}
 class Triangle{
    double a;
    double b;
    double c;
    public Triangle(){
    }
    public Triangle(double x,double y,double z){
        this.a=x;
        this.b=y;
        this.c=z;
    }
    public double round(){
        return a+b+c;
    }
    public double area(){
        double p=(this.a+this.b+this.c)/2.0;
        double x=Math.sqrt(p*(p-this.a)*(p-this.b)*(p-this.c));
        return x;
    }
}