Create class Rectangle with getdata() and putdata() methods

A class is a collection of objects that has common properties. It is a template for an object, and an object is an instance of a class. A class is declared by use of the class keyword. It has the following general syntax: 
class <classname> {
    type instance-variable1;
    .
    type instance-variableN;
 
 type methodname1(parameter-list) {
  // body of method
 }
    .
 type methodnameN(parameter-list) {
  // body of method
 }
}
Where, type is the data type of a variable which it may hold. A method has a return type such as void, int, etc. Creating an object is referred to an object. Objects of specific class are created using new operator which returns reference of that object. The syntax for creating an object of class is shown below: 
class_name  object_name;            // Create object reference

object_name  =  new  class_name( );   // Instantiating object of class
OR 
class_name  object_name  =  new  class_name( );  // Creating object

 In this program, we have created a Rectangle3 class that have two data members length and width. And we have created two methods getdata( ) and putdata( ) which gets the data and displays the data respectively. We are created the object of the Rectangle3 class by using new keyword and printing the objects value. Save this file by name RectArea.java. After compiling RectArea.java file we get two class files one is Rectangle3.class and other is RectArea.class then use RectArea.class file for running the program.

Note: Remember that you have to pass the class file name which contains the main( ) function while running the program.



PROGRAM
class Rectangle3 {
 
 int length, width;
 
 void getdata(int a, int b) {
  
  length = a;
  width = b;
 }
 
 void putdata() {
  
  System.out.println("Length = "+length);
  System.out.println("Width = "+width);
 }
}

public class RectArea {
 
 public static void main(String args[]) {
  
  Rectangle3 r1 = new Rectangle3();
  r1.putdata();
  r1.length = 15;
  r1.width = 25;
  r1.putdata();
 }
}
OUTPUT 
C:\>javac RectArea.java
C:\>java RectArea
Length = 0
Width = 0
Length = 15
Width = 25

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

Program to input age from user and throw user-defined exception if entered age is negative

An  Exception  is an abnormal condition that arises in a code sequence at run time. Exceptions are run time errors. Exceptions generated by the Java are related to the fundamental errors that violate the Java language constraints. All exception classes are subtypes of the  java.lang.Exception  class. The exception class is a subclass of the  Throwable  class. Java defines several exception classes inside the standard package  java.lang . Some examples of exceptions are  ArithmeticException, ArrayIndexOutOfBoundsException, IndexOutOfBoundsException, NullPointerException, NumberFormatException, ClassNotFoundException,etc. When Java Interpreter caught an error such as divide by zero, the interpreter creates an exception object and throws it to inform that an error has occurred. Java has its own exception handling mechanism. It performs the following task: Find the problem –  Hit  the exception Inform that an error has occurred –  Throw  the exception Receives the error infor
Read more