demosuper.java

it is a good tool to help you study java

class Box{
 private double width;     //这些成员被定义成私有
 private  double heigth;
 private  double depth;
Box(Box ob){
width=ob.width;
heigth=ob.heigth;
depth=ob.depth;
}
Box(double w,double h,double d){
width=w;
heigth=h;
depth=d;
}
Box(){
width=-1;
heigth=-1;
depth=-1;
}
Box(double len){
width=depth=heigth=len;
}
double vulume(){

return width*depth*depth;
}}
class BoxWeight extends Box{
double weight;
BoxWeight(BoxWeight ob){
super(ob);
weight=ob.weight;
}
BoxWeight(double w,double h,double d,double m){
super(w,h,d);
weight=m;
}
BoxWeight(){
super();
weight=-1;
}
BoxWeight(double len,double m){
super(len);
weight=m;
}
}
class DemoSuper{
public static void main(String args[]){
BoxWeight mybox1=new BoxWeight(10,20,15,34.3);
BoxWeight mybox2=new BoxWeight(2,3,4,0.076);
BoxWeight mybox3=new BoxWeight();//default
BoxWeight mycube=new BoxWeight(3,2);
BoxWeight myclone=new BoxWeight(mybox1);
double vol;
vol=mybox1.vulume();
System.out.println("Volume of mybox1 is"+vol);
System.out.println("Weight of mybox1 is"+mybox1.weight);
System.out.println();
vol=mybox2.vulume();
System.out.println("Volume of mybox2 is"+vol);
System.out.println("Weight of mybox2 is"+mybox1.weight);
System.out.println();
vol=mybox3.vulume();
System.out.println("Volume of mybox3 is"+vol);
System.out.println("Weight of mybox3 is"+mybox3.weight);
System.out.println();
vol=myclone.vulume();
System.out.println("Volume of myclone is"+vol);
System.out.println("Weight of myclone is"+myclone.weight);
System.out.println();
vol=mycube.vulume();
System.out.println("Volume of mycube is"+vol);
System.out.println("Weight of mycube is"+mycube.weight);
System.out.println();

}
}