OOP 1-3

Object-Oriented Programming (OOP)

A programming methodology that defines objects whose behaviors and interactions accomplish a given task; models real-world entities using objects.

Procedural Programming

Code divided into procedures and functions; works for small programs but hard to manage in large systems due to separation of data and logic.

Advantages of OOP

Less repetition, better organization, encapsulation, cleaner code, easier updates, scalability.

Class

A blueprint or template defining the structure (attributes) and behavior (methods) of objects.

Object (Instance)

A real entity created from a class; has its own data (state) and behaviors (methods).

State

Current values stored in an object’s attributes; can change during program execution.

Behavior

Actions an object can perform, defined by methods.

Attribute

A characteristic or property of an object; defined as fields/instance variables in a class.

Encapsulation

Bundling data (attributes) and methods into a single unit (class) to keep related logic together.

Inheritance

Reuse of code where a subclass acquires properties and methods of a superclass.

Polymorphism

Ability of different object types to respond to the same method call in different ways.

Constructor

Special method with the same name as the class; used to initialize objects; no return type.

Getter and Setter

Methods to read (get) and update (set) private attributes.

Method Signature

Includes method name and parameter types.

Method Overloading

Defining multiple methods with the same name but different parameter lists.

This keyword

Refers to the current object; used to distinguish instance variables from parameters.

Access modifiers

Control visibility of class members: - public: accessible from anywhere; - private: accessible only within the same class; - protected: accessible within the package and subclasses; - no modifier: accessible only within the package.

Static variable

Class-level variable shared among all instances; one copy only.

Static method

Belongs to the class, can be called without creating an object; can only access static members.

Instance variable

Declared in a class but outside any method; each object has its own copy.

Database analogy in OOP

Classes define structure; objects are like records with unique values in each field.