java，

java，

11.求圆的，长方形的面积周长

public class Cricle implements Shape2D{
double radius ;//定义圆的半径
public Cricle(double r){
radius=r;
}
    public double  grith(){
        return PI*radius*2;
    }
       public double area(){
      return PI*radius*radius;
       }
   
    }

public class Rectangle implements Shape2D {
double width,height;
public Rectangle(double w,double h){
width=w;
height=h;
}
public double grith() {
// TODO Auto-generated method stub
return 2*(width+height);
}


public double area() {
// TODO Auto-generated method stub
return width*height;
}


}


}

public interface Shape2D {
    final double  PI=3.14;
   double grith();
    double area();
    
}