Class, Object, Encapsulation, Inheritance | MAD - 1.0

Main ideas / concepts covered

Unit 1 prerequisite (OOP concepts)

• The video introduces core Object-Oriented Programming (OOP) concepts: Class, Object, Encapsulation, and Inheritance.
• These topics are important because:
  • Unit 1 + Unit 2 together have 5% weightage in an exam.
  • Typically, only one basic question is asked, usually requiring definitions of:
    • class
    • object
    • encapsulation
    • inheritance

---

Definitions and examples

1) Class

• Class = a blueprint/template used to create objects.
• It is a logical entity that defines:
  • what data an object will have
  • what methods an object will use
• Memory/usage idea:
  • the class defines the structure, but
  • meaningful storage/usage happens when an object is created
• Example:
  • A class named Car contains properties related to a car such as:
    • wheels
    • engine

2) Object

• Object = the real-world entity created from a class.
• It is described as:
  • an instance of the class
  • created at runtime
• When created, it occupies memory space in the computer.
• Example:
  • From class Car, an object could be:
    • a red Toyota Corolla
  • This instance can be called:
    • an object
    • an instance of the class

3) Encapsulation

• Encapsulation is the process of combining (wrapping) data and methods into a single unit, likened to a capsule.
• Purpose / lesson:
  • internal data (variables) should be confidential
  • it should not be directly exposed to outside code/users
• Key benefit:
  • Hiding protects internal state, so outsiders cannot directly access and change it
• Example (bank account scenario):
  • If a class BankAccount exposes the balance variable as public:
    • someone could directly modify it (e.g., set it to 10 million) without authorization
  • Correct approach:
    • keep balance private
    • allow updates only through a proper method (e.g., a deposit method) so changes are controlled

4) Inheritance

• Inheritance is a mechanism where:
  • one class acquires the properties and behavior of another class
• Terms:
  • Parent class: the class being inherited from
  • Child class: the class that inherits
• Benefits / lesson:
  • enables code reuse
  • avoids rewriting the same code repeatedly
• Example:
  • Animal is the parent class with general features like:
    • eat
    • sleep
  • Dog is the child class that inherits from Animal
  • Therefore, Dog also has eat and sleep

---

Methodology / instruction-like content (bullet points)

• For exam preparation (implied study focus):
  • Know and be able to define:
    • class
    • object
    • encapsulation
    • inheritance
• Encapsulation practice (conceptual instruction):
  • Wrap data and methods into one unit (capsule-like)
  • Hide internal variables (e.g., use private for sensitive data)
  • Allow updates only via controlled methods (e.g., deposit method for balance)
• Inheritance practice (conceptual instruction):
  • Create a child class that inherits from a parent class to reuse properties/behavior
  • Example pattern: Dog inherits from Animal

---

Speakers / sources featured

• No specific speaker name or source is identified in the subtitles.