Program to use inheritance to extend Box class

Like methods, constructors can also be overloaded. Constructor overloading is way of having more than one constructor which does different tasks. For e.g. Vector class has 4 types of constructors. If you do not want to specify the initial capacity and capacity increment then you can simply use default constructor of Vector class like this
Vector v = new Vector( );

In this program, we have created a class Box1 which have four constructors one is default and other three are parameterized constructors. Then we extended the class Box1 in BoxWeight1. At last we have created object of BoxWeight1 and called the method volume( ).
PROGRAM
//This program uses inheritance to extend Box.
class Box1 {
 double width;
 double height;
 double depth;

 // construct clone of an object
 Box1(Box1 ob) { // pass object to constructor
  width = ob.width;
  height = ob.height;
  depth = ob.depth;
 }

 // constructor used when all dimensions specified
 Box1(double w, double h, double d) {
  width = w;
  height = h;
  depth = d;
 }

 // constructor used when no dimensions specified
 Box1() {
  width = -1; // use -1 to indicate
  height = -1; // an uninitialized
  depth = -1; // box
 }

 // constructor used when cube is created
 Box1(double len) {
  width = height = depth = len;
 }
 // compute and return volume
 double volume() {
  return width * height * depth;
 }
}

//Here, Box is extended to include weight.
class BoxWeight1 extends Box1 {
 double weight; // weight of box

 // constructor for BoxWeight
 BoxWeight1(double w, double h, double d, double m) {
  width = w;
  height = h;
  depth = d;
  weight = m;
 }
}

class DemoBoxWeight {
 public static void main(String args[]) {
  BoxWeight1 mybox1 = new BoxWeight1(10, 20, 15, 34.3);
  BoxWeight1 mybox2 = new BoxWeight1(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);
 }
}
OUTPUT 
C:\>javac DemoBoxWeight.java
C:\>java DemoBoxWeight
Volume of mybox1 is 3000.0
Weight of mybox1 is 34.3

Volume of mybox2 is 24.0
Weight of mybox2 is 0.076

Popular posts from this blog

Program to define a class 'employee' with data members as empid, name and salary. Accept data for 5 objects using Array of objects and print it.

This program demonstrates you the array of objects.  Array of object  is the collection of objects of the same class. The given syntax will define an array of reference therefore assign object to individual reference in the array to declare the array of object. The syntax to define array of object is: <class-name> <array-name> [size]; For example, the following statement will define an array of object having size 6 references to the class  Box . Box b[6]; For creating an array of objects (allocating memory) you have to write down the following statements for (int i=0; i<6; i++) { b[i] = new Box(); // Assigning object to individual reference in the array. } PROGRAM import java.util.Scanner; public class Employee { int empid; String name; float salary; public void getInput() { Scanner in = new Scanner(System.in); System.out.print("Enter the empid :: "); empid = in.nextInt(); System.out.print("Enter the name :: ");
Read more

Define a class Student with four data members such as name, roll no.,sub1, and sub2. Define appropriate methods to initialize and display the values of data members. Also calculate total marks and percentage scored by student.

In this program, first we first create a class  Student  which have data members  name, roll_no, sub1, sub2  and one method to read data here  getdata( )  method and show the result here  show( )  method. We have used  java.io.BufferedReader  class to read data from keyboard at runtime. Then we have created an object of Student class in  StudentDemo  class and called the methods of Student class. When you compile the code using  javac StudentDemo.java  command two .class files will be created which are  Student.class  and  StudentDemo.class , this has the advantage that you can reuse your .class file somewhere in other projects without compiling the code again. You can create as many classes as you want but writing many classes in a single file is not recommended as it makes code difficult to read rather you can create single file for every class. You can also group classes in packages for easily managing your code. PROGRAM import java.lang.*; import java.io.*; class Student
Read more