第十一次实验课代码

添加C08~C011

C06 Polymorphism/src/shape/Shape.java

@@ -1,7 +1,7 @@
 package shape;
 import java.awt.*;
 
-public class Shape {
+public abstract class Shape {
     protected Color color;
     protected int x,y;
 
@@ -11,9 +11,7 @@ public class Shape {
     public Color getColor() {
         return color;
     }
-    public double getArea(){
-        return x*y;
-    }
+    public abstract double getArea();
 
     public void setX(int x){
         this.x=x;
@@ -29,9 +27,7 @@ public class Shape {
         return y;
     }
 
-    public double getPerimeter(){
-        return x*y;
-    }
+    public abstract double getPerimeter();
 
     public void move(int dx,int dy){
         x += dx;