package exit5;
public class testabstract {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
Shape shape1,shape2;
shape1=new Rectangle(10.0,20.0);
shape1.showarea();
shape2=new Circle(10.0);
shape2.showarea();
shape2.resize(0.2);
shape2.showarea();
}
}package exit5;
public abstract class Rectangle extends Shape {
double w,h;
public Rectangle(double h0 ,double w0) {
// TODO Auto-generated constructor stub
h=h0;w=w0;
}
double getarea(){
return h*w;
}
void resize(double factor){
w*=factor;h*=factor;
}
}
------解决方案--------------------------------------------------------
abstract class couldn't be instance.