Defining a class


  • A class is the basic element of object oriented programming.
  • A class defines the shape and behavior of an object.
  • A class is a template for multiple object with similar feature.

Any concept represented in a class is encapsulated in a class. When an application is written, classes of objects are defined.

To create a class a keyword ‘class’ followed by curly brackets is used. As shown below

class   {

A class called Professor includes all its features serving as template for the concepts. Each property treated as an attribute of that class.

In Java attributes are declared inside the class.

For example, the professor’s name, professors mobile are its attributes. The definition of the class ‘Professor’ would be:

class Professor {
String professorName;
String professorAddres;
int mobile;

Apart from defining an object’s structure, a class also defines its functional interface, known as methods.

To create a method, syntax is as shown below

class {
return_type  method_name(){
In Java each method requires a class.

For example, the class ‘Professor’ can have a method ( showProfessorName)  that display the name of the professor,

class Professor {
String professorName;
String professorAddress;
int mobile;
void showProfessorName(){
        System.out.println("Name of the professor is" +name);

Once a class ‘Professor’ is defined, instance (object) of that class can be created and each instance can have different attributes. When the program runs, instances of the class are created and discarded as when required.

An instance can be created in a method of class only.

The terms instance and object are used interchangeably.

For example,
class Professor {
String professorName;
String professorAddress;
int mobile;
void showProfessorName(){
        System.out.println("Name of the professor is" +professorName);
void showProfessorAddress(){
        System.out.println("Name of the professor is" +professorAddress);
        Professor p = new Professor(); // Object p of class 'Professor'
        p.showProfessorName(); // p called method
        System.out.println("mobile is"; // p called attribute

Python Programming ↓ 👆
Java Programming ↓ 👆
JAVA covered following topics in these notes.
JAVA Programs
Principles of Programming Languages ↓ 👆
Principles of Programming Languages covered following topics in these notes.

Previous years solved papers:
A list of Video lectures References:
  1. Sebesta,”Concept of programming Language”, Pearson Edu 
  2. Louden, “Programming Languages: Principles & Practices” , Cengage Learning 
  3. Tucker, “Programming Languages: Principles and paradigms “, Tata McGraw –Hill. 
  4. E Horowitz, "Programming Languages", 2nd Edition, Addison Wesley

    Computer Organization and Architecture ↓ 👆

    Computer Organization and Architecture covered following topics in these notes.

    1. Structure of desktop computers
    2. Logic gates
    3. Register organization
    4. Bus structure
    5. Addressing modes
    6. Register transfer language
    7. Direct mapping numericals
    8. Register in Assembly Language Programming
    9. Arrays in Assembly Language Programming


    1. William stalling ,“Computer Architecture and Organization” PHI
    2. Morris Mano , “Computer System Organization ”PHI

    Computer Network ↓ 👆
    Computer Network covered following topics in these notes.
    1. Data Link Layer
    2. Framing
    3. Byte count framing method
    4. Flag bytes with byte stuffing framing method
    5. Flag bits with bit stuffing framing method
    6. Physical layer coding violations framing method
    7. Error control in data link layer
    8. Stop and Wait scheme
    9. Sliding Window Protocol
    10. One bit sliding window protocol
    11. A protocol Using Go-Back-N
    12. Selective repeat protocol
    13. Application layer
    1. Andrew S. Tanenbaum, David J. Wetherall, “Computer Networks” Pearson Education.
    2. Douglas E Comer, “Internetworking with TCP/IP Principles, Protocols, And Architecture",Pearson Education
    3. KavehPahlavan, Prashant Krishnamurthy, “Networking Fundamentals”, Wiley Publication.
    4. Ying-Dar Lin, Ren-Hung Hwang, Fred Baker, “Computer Networks: An Open Source Approach”, McGraw Hill.