PPS Unit 5 One Shot | SPPU | Object Oriented Programming in Python | #python #sppu #pps

Introduction to Programming Paradigms

Commitment to Learning

• The speaker emphasizes a strong commitment to learning, stating that once a promise is made, they do not listen to anyone else, including themselves.

Overview of Programming Paradigms

• A programming paradigm is defined as an approach or method for designing computer programs. It encompasses various ways to structure and organize code.

• Different programming paradigms have distinct sets of rules and methodologies for program design. This diversity allows programmers to choose the most suitable paradigm for their needs.

Types of Programming Paradigms

Monolithic Programming Paradigm

• In monolithic programming, programs are designed as a single cohesive unit, meaning all functionalities are tightly coupled and interconnected within one structure.

• The tight coupling of components in monolithic programming leads to challenges in scalability, maintainability, and modifications since changes in one component can affect others automatically.

• Examples of languages that follow the monolithic paradigm include COBOL and Assembly language. These languages exemplify the characteristics of tightly integrated program structures.

Procedural Programming Paradigm

• Procedural programming focuses on defining a series of procedures or routines executed sequentially to solve problems, enhancing simplicity and reducing complexity in smaller programs.

• While effective for simple tasks, procedural programming can become complex when managing larger programs due to its sequential execution nature which increases time and space complexity over time. Understanding these complexities will be crucial in future studies related to data structures and algorithms (DSA).

• Examples include Pascal and ALGOL languages which illustrate procedural approaches effectively but may struggle with larger applications due to inherent limitations in handling complexity.

Structured Programming Paradigm

Characteristics of Structured Programming

• Structured programming is based on a procedure-oriented approach that relies heavily on functions and logic while following a top-down design methodology for problem-solving. This method encourages breaking down complex problems into manageable parts through hierarchical structuring.

• Similar to procedural programming, structured programming is less suitable for managing large-scale complex programs due to its limitations in handling extensive systems efficiently; it shares similar drawbacks with procedural paradigms regarding scalability issues.

• Notable examples include C language which adheres closely to structured principles learned during foundational courses like FPL (Fundamentals of Programming Languages).

Object-Oriented Programming Overview

Focus on Objects and Classes

• Object-oriented programming (OOP) centers around the concepts of objects and classes; further details about these concepts will be elaborated upon in subsequent slides or discussions as they form the core foundation of OOP principles essential for understanding advanced topics within this paradigm framework.

Understanding Object-Oriented Programming

Introduction to Object-Oriented Programming (OOP)

• OOP is dependent on objects and classes, which will be explained in detail in the next slides.

• It promotes code reuse, modularity, and scalability, enhancing the overall structure of programming.

• Python supports both structured programming paradigms but excels in object-oriented programming.

Features of Object-Oriented Programming

• High-level languages like Python, Java, and C++ follow the object-oriented programming paradigm.

• Key features of OOP include:

• Classes and Objects

• Methods and Message Passing

• Inheritance

• Polymorphism

• Containment

• Reusability and Delegation

• Data Abstraction and Data Encapsulation

Classes and Objects Explained

• Classes serve as blueprints for creating objects; they define attributes and behaviors.

• An object is an instance of a class that contains real data and behavior. For example:

• A "Student" class may have attributes like name, age, classroom number, etc.

Examples to Illustrate Concepts

• The "Student" class can have multiple instances such as Student One (Suyash), Student Two (Riya), etc., representing individual students as objects.

• Another example is a "Country" class with attributes like population, GDP, number of states. Instances could include India or USA.

Conclusion on Class vs. Object Understanding

• The distinction between classes (blueprints for data structures) and objects (instances containing specific data).

• Further examples clarify how different countries represent objects within the country class blueprint.

Understanding Object-Oriented Programming Concepts

Importance of Object-Oriented Programming in Exams

• The speaker emphasizes that the upcoming exams will feature numerous questions on Object-Oriented Programming (OOP), particularly focusing on the last unit of the syllabus.

• Students are advised to study this unit thoroughly, as it is crucial and not optional.

Introduction to Classes and Objects

• The speaker begins by executing a program related to classes and objects, intending to teach how they function.

• A class is created simply by writing "class" followed by its name; for example, "Car" serves as a blueprint for creating car objects.

Creating Objects from Classes

• To create an object, one writes the object's name followed by the class name using an equal sign. For instance, "car1 = Car()" creates an object named car1.

• The class acts as a blueprint where all code related to the object is stored, indicating that any information about the object will be kept within this structure.

Understanding Class Attributes and Methods

• When creating instances like "Toyota" and "Corolla," these values are passed into the class through functions known as constructors.

• The underscore notation indicates a constructor method which helps access information about objects effectively.

Working with Instance Variables

• Instance variables such as self.brand and self.model store specific attributes of each object created from the class.

• When calling methods or functions associated with these objects, positional arguments determine where data like brand and model are assigned.

Outputting Object Information

• By printing attributes like car1.brand or car2.model, students can see how values are retrieved based on their positions in the constructor call.

• This process illustrates how classes and objects work together in OOP, reinforcing understanding through practical examples.

Defining Methods in Classes

• Methods refer to functions defined inside a class; they serve similar purposes but are specifically termed differently in OOP contexts.

• Understanding methods is essential since they encapsulate functionality relevant to their respective classes.

Message Passing in OOP

• Message passing refers to communication between objects via method calls. It involves sending messages (data/arguments).

Introduction to Methods and Message Passing

Overview of Class and Function Definition

• The discussion begins with the introduction of a simple program focusing on methods and message passing, specifically within a class named Greeting.

• The instructor notes that constructors are optional in Python classes; if not explicitly defined, Python automatically creates one.

• An object named g is created from the Greeting class, demonstrating how to instantiate an object using the class name.

Understanding Message Passing

• The concept of message passing is introduced as calling methods (like hello) through an object's instance.

• A variable name stores the argument passed (Suyash), which is then printed as part of the output: "Hello Suyash".

Concept of Methods in Object-Oriented Programming

Defining Methods and Their Purpose

• The term 'method' is clarified as synonymous with 'function' in object-oriented programming (OOP).

• Emphasis is placed on interconnectedness in programming units; neglecting one unit can lead to issues across others.

Inheritance in Object-Oriented Programming

Introduction to Inheritance

• Inheritance allows one class to inherit properties and methods from another, enhancing code reusability.

• An analogy is drawn between countries and states, explaining that if a country has a property (like democracy), its states will also inherit this property.

Types of Inheritance

• Various types of inheritance are mentioned: single inheritance, multiple inheritance, multilevel inheritance, hierarchical inheritance, and hybrid inheritance.

Single Inheritance Explained

Characteristics of Single Inheritance

• Single inheritance involves a child class inheriting from only one parent class. This means it derives properties from just one source.

Example Implementation

• An example involving an Animal class demonstrates defining methods like Speak, which will be inherited by subclasses such as Dog.

Understanding Inheritance in Programming

Single Inheritance

• The speaker introduces the concept of the speak function within a Dog object, which inherits from an Animal class. This demonstrates how methods can be accessed through inheritance.

• Outputs are generated showing that both the Animal speaks and Dog barks, indicating successful method calls from both classes. This illustrates single inheritance where properties of the parent class (Animal) are accessible in the child class (Dog).

• The speaker explains that single inheritance allows a child class to inherit properties from one parent class, emphasizing its simplicity and effectiveness.

Multiple Inheritance

• Transitioning to multiple inheritance, it is defined as when a child class inherits from multiple parent classes, allowing access to various properties.

• An example is provided with two parent classes (Parent One and Parent Two) contributing their properties to a single child class. This showcases how multiple sources can enrich a child's capabilities.

• The necessity of creating only the child class's object is highlighted; this suffices for accessing methods from all inherited classes due to implemented multiple inheritance.

Multilevel Inheritance

• Multilevel inheritance is introduced as a structure where one class inherits from another, forming a chain of inheritance (e.g., Grandparent → Parent → Child).

• The speaker describes how properties flow downwards: the grandparent provides attributes to the parent, which then passes them on to the child.

• It’s noted that even if some classes appear empty (like Parent), they still inherit attributes indirectly through their ancestors.

Hierarchical Inheritance

• Hierarchical inheritance involves multiple child classes inheriting from a single parent class. This structure allows shared properties among different subclasses.

• An analogy using countries and states illustrates hierarchical relationships: India as a parent with states like Maharashtra and Gujarat as children receiving common attributes (e.g., democracy).

• The process of creating objects for each child class is briefly mentioned, reinforcing understanding without delving into specifics about object creation.

Hybrid Inheritance

• Hybrid inheritance combines elements of various types of inheritance discussed earlier. It represents an advanced form where characteristics of two or more types coexist within one framework.

Inheritance in Object-Oriented Programming

Understanding Class Inheritance

• The discussion begins with the concept of inheritance, highlighting a combination of classes: A, B, C, and D.

• Class B inherits properties from Class A, indicating single inheritance between these two classes.

• Class C also inherits properties from Class A, establishing a hierarchical inheritance structure with one parent (A) and multiple children (B and C).

• Class D demonstrates multiple inheritance by accessing properties from both Classes B and C.

• The overall example illustrates various types of inheritance including single, hierarchical, multiple, and hybrid inheritance.

Polymorphism in Object-Oriented Programming

Key Features of Polymorphism

• Polymorphism is defined as a foundational concept in object-oriented programming that allows functions and methods to behave differently based on data type.

• It enables defining methods with the same name across different classes; execution depends on the class context at runtime.

• An example is provided where both Bird and Dog classes define a method named sound, showcasing how polymorphism works when calling this method.

• When iterating through instances of both classes using a common interface (Animal), it prints outputs specific to each class's implementation of the sound method.

• The essence of polymorphism is reiterated: different classes can have methods with the same name but distinct behaviors.

Composition in Object-Oriented Programming

Exploring Composition

• Composition is introduced as a way for one class to contain objects of another class, facilitating complex object creation by combining simpler ones.

• This approach addresses limitations faced by procedural programming when managing large or complex programs; OOP handles them effectively through features like composition.

• An example program illustrates composition via an Engine class being utilized within a Car class.

Understanding Object-Oriented Programming Concepts

Class and Object Creation

• The discussion begins with the concept of creating an object from a class, specifically using the example of a "Car" class. When an object is created, certain methods automatically run.

• It highlights the importance of capitalization in naming conventions for classes and objects, emphasizing that an instance of the "Engine" class is created within the "Car" class.

• This leads to the introduction of Container Ship, which refers to creating one class's object inside another class.

Key Features: Reusability and Delegation

• The speaker explains Reusability as the ability to reuse code through inheritance and container ship, while Delegation involves one object assigning tasks to another.

• Reusability allows developers to avoid redundancy by leveraging existing code structures, enhancing efficiency in programming.

Data Abstraction and Encapsulation

• Data Abstraction is defined as hiding internal details while showing only functionality; it serves privacy and security purposes in software development.

• Companies often use data abstraction to limit user access to sensitive information, ensuring that only necessary data is visible.

• Encapsulation combines data and methods into a single unit (class), allowing for better organization and management of related functionalities.

Understanding Self Argument in Classes

• The term Self refers to the current instance of a class. It plays a crucial role in accessing attributes within methods defined in that class.

• An example illustrates how defining a method with self allows access to instance-specific information when an object is created.

Constructor and Destructor Methods

• The Init Method, or constructor, is automatically called when an object is created. It initializes attributes without needing explicit calls from users.

• Following this, it's explained that every class should ideally have an init method as its first function for proper initialization.

Deleting Objects: Destructor Method

Understanding Class and Object Variables in Programming

Class and Object Variables

• The discussion begins with the concept of creating and deleting objects in programming, emphasizing that to create an object, one must write the object's name along with the class name.

• Class variables are defined within a class but outside any methods. These variables can be used throughout the class.

• Object variables are defined within the methods of a class using the self keyword. This means that any variable created with self is considered an object variable.

• An example is provided where a Student class has a variable named school, which stores data ("ABC High School") as a class variable since it resides within the class itself.

• The distinction between class variables (defined inside the class) and object variables (defined using self) is clarified, highlighting their respective scopes.

Public and Private Members

• Public members are accessible from anywhere, both inside and outside of the class. An example shows how a public member (self.name = "Suyash") can be accessed freely.

• In contrast, private members cannot be directly accessed from outside the class. A demonstration includes creating a private member (self._secret = "hidden message") which starts with an underscore to indicate its privacy.

• It is emphasized that private members should start with an underscore; this convention signifies that they are not meant for external access.

• Attempting to access a private member from outside its defining class will result in an error, reinforcing their restricted accessibility.

• The session concludes by summarizing public members' accessibility compared to private members while inviting viewers to comment on which feature does not belong to OOP among several options presented.