Object-Oriented Programming (OOPs) from Zero to Advanced

Importance of OOPs

• Essential for interviews (placements, internships, college exams)
• Strong understanding is crucial for programming and working in companies
• Helps in better code organization, especially at the organizational level

Structure of the Lecture

• Theory concepts
• Practical examples
• Key definitions
• Coding in C++
• 30 MCQ questions at the end for reinforcement

Key Concepts in OOPs

• Classes and Objects

  • Class: Blueprint for objects (e.g., car blueprints in Toyota's factory)
  • Object: Instance of a class (pen, laptop in real life)
  • Example: College system managing teachers' details (name, department, subject, salary)

• Encapsulation

  • Combination of data (properties) and methods (functions)
  • Example: Teacher class with properties and functions (changeDepartment)
  • Concept ensures data hiding within classes using private, protected, and public access specifiers

• Access Specifiers

  • Private: Accessible only within the class
  • Protected: Accessible within the class and derived classes
  • Public: Accessible everywhere

• Constructors and Destructors

  • Constructor: Initializes an object when it's created
    • Types: Non-parameterized, Parameterized, Copy constructor
  • Destructor: Cleans up when an object is destroyed
  • Example: Teachers' salary set through constructors

• Inheritance

  • Concept of one class (child) inheriting properties and methods from another class (parent)
  • Promotes code reusability
  • Example: Person class inherited by Student class
  • Types: Single, Multi-Level, Multiple, Hierarchical, Hybrid
  • Constructor and Destructor Call Order: Parent first, then child

• Polymorphism

  • Ability of different objects to behave in different ways
  • Compile-time: Function Overloading, Constructor Overloading
  • Runtime: Function Overriding, Virtual Functions
  • Example: Show function in Print class printing integers and characters differently

• Abstraction

  • Hiding unnecessary details and showing only the essential parts
  • Achieved through access specifiers and abstract classes
  • Example: Shape class as an abstract class with a pure virtual function draw

• Static Keyword

  • Static Variables: Shared among all objects of a class
  • Static Functions: Can be called without an object
  • Example: Maintaining a static counter for the number of objects created

Practical Coding Examples

• Creating and using classes and objects
• Implementing encapsulation, inheritance, polymorphism, and abstraction
• Using access specifiers effectively
• Understanding constructor and destructor behavior
• Working with static members

Review and Practice

• 30 MCQs at the end of the lecture to test understanding
• Create thorough notes and understand definitions
• Practice coding examples to reinforce concepts
• Aim for a strong grasp of all main OOPs concepts for interviews and exams

Conclusion

• OOPs concepts are fundamental and widely used in many programming languages beyond C++
• Good understanding helps in interviews and practical programming tasks
• Keep learning and applying OOPs concepts, good luck with your internships and placements!