package shape;

public class Shape

{

    //定义成员变量

    private double zhouchang;

    private double mianji;

    public double getZhouchang() {

        return zhouchang;

    }

    public void setZhouchang(double zhouchang) {

        this.zhouchang = zhouchang;

    }

    public double getMianji() {

        return mianji;

    }

    public void setMianji(double mianji) {

        this.mianji = mianji;

    }

}

package shape;

public class Sanjiao extends Shape

{

    //定义新的成员方法用来求周长

    public String qiuZC(double bian1,double bian2,double bian3)

    {

        if((bian1+bian2)>bian3&&(bian2+bian3)>bian1&&(bian1+bian3)>bian2)

            return "三角形的周长为："+(bian1+bian2+bian3);

        else

            return "该三角形的边长不合法，两边之和必须大于第三边";        

    }

}

package shape;

public class Jvxing extends Shape

{

    //定义新的成员方法用来求周长

    public String qiuZC(double chang, double kuan)

    {

        if(chang>0&&kuan>0)

            return "矩形的周长为："+2*(chang+kuan);

        else

            return "该矩形的长和宽不合法，长和宽必须大于0";

    }

}

package shape;

public class E {

    public static void main(String[] args) {

        //实例化三角形对象

        Sanjiao sj = new Sanjiao();

        System.out.println(sj.qiuZC(5, 5.6, 8));

        System.out.println(sj.qiuZC(5, 5.6, 25.2));

        //实例化矩形对象

        Jvxing jx= new Jvxing();

        System.out.println(jx.qiuZC(5, 5.6));

        System.out.println(jx.qiuZC(28, 0));

    }

}