定义一个抽象类SHAPE,在其中声明计算面积AREA()和周长PERINETER（）方法,定义矩形类RECTANGLE和圆形类CI

我有个类似的,你看一下
import java.awt.*;
import java.applet.*;
abstract class Shapes
{
protected int x,y,k;
protected double m;
public Shapes(int x,int y,int k,double m)
{this.x=x; this.y=y;
this.k=k; this.m=m;
}
abstract public double getArea();
abstract public double getPerimeter();
}
class Rect extends Shapes
{ public double getArea()
{ return(k*m); }
public double getPerimeter()
{ return(2*k+2*m);}
public Rect(int x,int y,int width,int height)
{ super(x,y,width,height);}
}
class Triangle extends Shapes
{ public double getArea()
{return(Math.sqrt(m*( m-k)*( m-x)*(m-y)));}
public double getPerimeter()
{return(k+x+y);}
public Triangle(int baseA,int baseB,int baseC)
{ super(baseA,baseB,baseC,0);
m= (baseA+ baseB+ baseC)/2.0;
}
}
class Circle extends Shapes
{ public double getArea()
{return(m* m *Math.PI);}
public double getPerimeter()
{return(2*Math.PI* m);}
public Circle(int x,int y,int width)
{
super(x,y,width,width/2.0);
}
}
public class RunShape extends Applet
{ Rect rect=new Rect(5,15,25,25);
Triangle tri=new Triangle(5,5,8);
Circle cir =new Circle(13,90,25);
public void paint(Graphics g)
{
g.drawRect(rect.x,rect.y,rect.k,(int)rect.m);
g.drawString("Rect Area:"+rect.getArea(),50,35);
g.drawString("Rect Perimeter:"+rect.getPerimeter(),50,55);
g.drawString("Triangle Area:"+tri.getArea(),50,75);
g.drawString("Triangle Perimeter:"+tri.getPerimeter(),50,95);
g.drawOval(cir.x-(int)cir.k/2,cir.y-(int)cir.k/2,cir.k,cir.k);
g.drawString("Circle Area:"+cir.getArea(),50,115);
g.drawString("Circle Perimeter:"+cir.getPerimeter(),50,135);
}
}