Member Access and Inheritance

Member Access and Inheritance:

Although a subclass includes all of the members of its superclass, but cannot access those members of the superclass that  declare as private.


Here the Example :

// This program uses inheritance to extend Box.


class Box {
  double width;
  double height;
  double depth;
  // construct clone of an object
  Box(Box ob) { // pass object to constructor
    width = ob.width;
    height = ob.height;
    depth = ob.depth;
  }



// constructor used when all dimensions specified


  Box(double w, double h, double d) {
    width = w;
    height = h;
    depth = d;
  }


  // constructor used when no dimensions specified


  Box() {
    width = -1;  // use -1 to indicate
    height = -1; // an uninitialized
    depth = -1;  // box
  }


// constructor used when cube is created


  Box(double len) {
    width = height = depth = len;
  }

  // compute and return volume


  double volume() {
    return width * height * depth;
  }
}


// Here, Box is extened to include weight.


class BoxWeight extends Box {
  double weight; // weight of box
  // constructor for BoxWeight
  BoxWeight(double w, double h, double d, double m) {
    width = w;
    height = h;
    depth = d;
    weight = m;
  } 
}


class DemoBoxWeight {
  public static void main(String args[]) {
    BoxWeight mybox1 = new BoxWeight(10, 20, 15, 34.3);
    BoxWeight mybox2 = new BoxWeight(2, 3, 4, 0.076);
    double vol;
    vol = mybox1.volume();
    System.out.println("Volume of mybox1 is " + vol);
    System.out.println("Weight of mybox1 is " + mybox1.weight);
    System.out.println();
    vol = mybox2.volume();
    System.out.println("Volume of mybox2 is " + vol);
    System.out.println("Weight of mybox2 is " + mybox2.weight);
  }
}