?? ch9ex11.java
字號:
class Shape {
void draw(){}
void erase(){}
}
class Circle extends Shape{
void draw(){
System.out.println("Circle.draw()");
}
void erase(){
System.out.println("Circle.erase()");
}
}
class Square extends Shape{
void draw(){
System.out.println("Square.draw()");
}
void erase(){
System.out.println("Square.erase()");
}
}
class Triangle extends Shape{
void draw(){
System.out.println("Triangle.draw()");
}
void erase(){
System.out.println("Triangle.erase()");
}
}
public class ch9ex11{
public static Shape randShape(){
switch((int)(Math.random()*3)){
case 0: return new Circle();
case 1: return new Square();
case 2: return new Triangle();
default:return null;
}
}
public static void main(String[] args){
Shape s[]=new Shape[9];
for(int j=0;j<s.length;j++)
s[j]=randShape();
for(int j=0;j<s.length;j++)
s[j].draw();
}
}
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