Fundamental Concepts of Object Oriented Programming
Summary
TLDRThis script introduces the core principles of object-oriented programming (OOP): abstraction, encapsulation, inheritance, and polymorphism. It explains how abstraction simplifies real-world complexity for software applications, encapsulation hides object complexities, and inheritance allows classes to derive properties and methods from others, creating a hierarchy. Polymorphism enables subclasses to implement inherited methods uniquely, showcasing OOP's power in creating flexible, reusable code.
Takeaways
- 🧩 **Abstraction**: Simplifies reality by focusing only on the data and processes relevant to the application being built.
- 📦 **Encapsulation**: Binds data and the programs that manipulate it together, hiding their complexity from the outside.
- 🔄 **Inheritance**: Allows a class to derive its methods and properties from another class, creating a hierarchy of superclasses and subclasses.
- 🌟 **Polymorphism**: Enables a class to implement an inherited method in its own way, allowing different subclasses to behave differently despite sharing the same interface.
- 🚗 **Objects in OOP**: Represent real-world entities or concepts that the software application is interested in, both physical and abstract.
- 📘 **Classes as Templates**: Serve as blueprints for creating objects, defining their attributes and operations (methods).
- 🔑 **Properties and Methods**: Properties describe an object's data, while methods are the actions that can be performed on or by the object.
- 🌐 **Instantiation**: The process of creating an object from a class, making each object a unique instance with its own state.
- 🔗 **Constructors**: Special methods used during instantiation to assign initial values to an object's properties.
- 🛡️ **Information Hiding**: A principle of encapsulation that protects the internal state of an object from external interference and misuse.
- 🔀 **Type Relationships**: Inheritance defines 'is-a' relationships, where subclasses are specific types of their base classes.
Q & A
What are the four fundamental concepts of object-oriented programming?
-The four fundamental concepts of object-oriented programming are abstraction, encapsulation, inheritance, and polymorphism.
What is an object in the context of object-oriented programming?
-An object in object-oriented programming is anything of interest to the software application being built, which can be a physical thing like a car or a non-physical entity like a bank account.
What is abstraction in object-oriented programming?
-Abstraction in object-oriented programming is the process of simplifying reality to focus only on the data and processes that are relevant to the application being built.
What is a class and how does it relate to objects?
-A class is a template for creating objects, defining the attributes (properties) and operations (methods) of an object. It is used to instantiate objects, which are instances of the class.
What is encapsulation and why is it important?
-Encapsulation is the concept of hiding the complexity of an object's inner workings from the outside. It is important for information hiding and ensuring the integrity and safety of the data and operations within the object.
How does inheritance work in object-oriented programming?
-Inheritance allows a class to derive its methods and properties from another class, creating a hierarchy of classes where a subclass inherits features from its superclass.
What is polymorphism and how does it relate to object-oriented programming?
-Polymorphism allows a class to implement an inherited method in its own way, enabling different subclasses of the same superclass to behave differently despite sharing the same interface.
What is a constructor in the context of object-oriented programming?
-A constructor is a special method used during the instantiation of an object, allowing the assignment of values to properties at the time of object creation.
How does the concept of a 'state' of an object relate to its properties?
-The 'state' of an object refers to the values assigned to its properties, making each object of the same type a unique entity.
What is the difference between a base class and a subclass in terms of inheritance?
-A base class is the class at the start of the inheritance hierarchy, while a subclass is any class that derives from another class, inheriting its methods and properties.
Why is it beneficial for a programmer to use a class library?
-Using a class library is beneficial because it simplifies the use of objects and ensures that the data and operations encapsulated within are safe, without needing to understand the inner workings of the class.
Outlines
📚 Introduction to Object-Oriented Programming Concepts
The paragraph introduces the core concepts of object-oriented programming (OOP): abstraction, encapsulation, inheritance, and polymorphism. It begins by defining an object as a real-world entity or an abstract concept that a software application interacts with. The paragraph explains abstraction as the process of simplifying complex realities to focus on relevant data and tasks. A class is described as a blueprint for creating objects, detailing its attributes (or properties) and operations (or methods). The paragraph also touches on instantiation, where objects are created from classes, and the role of constructors in setting initial property values. Encapsulation is introduced as a means to hide the internal workings of an object, ensuring data integrity and protecting it from external interference.
🔗 Inheritance and Polymorphism in OOP
This paragraph delves into the concepts of inheritance and polymorphism within OOP. Inheritance allows a class to derive methods and properties from another class, creating a hierarchy of classes. It uses the example of a 'Person' class and how 'Employee' and 'Customer' classes can inherit from it, potentially extending it with additional properties and methods. The paragraph also discusses the notion of a base class, subclasses, and superclasses in the context of inheritance. Polymorphism is explained as the ability of subclasses to implement inherited methods in their own unique ways, allowing different behaviors while maintaining the same interface. The paragraph concludes by summarizing the four fundamental concepts of OOP, emphasizing how they contribute to building robust and maintainable software applications.
Mindmap
Keywords
💡Object
💡Abstraction
💡Class
💡Encapsulation
💡Inheritance
💡Polymorphism
💡Instantiation
💡Properties
💡Methods
💡Constructor
💡Interface
Highlights
The four fundamental concepts of object-oriented programming are abstraction, encapsulation, inheritance, and polymorphism.
An object can represent anything of interest to a software application, including both physical and non-physical entities.
Abstraction simplifies reality by focusing on relevant data and tasks for the application being built.
A class is a template for creating objects, defining their attributes and operations.
Attributes describe the object's properties, while operations are the actions that can be performed by the object.
Objects are instances of classes, created through a process called instantiation.
Encapsulation hides the complexity of an object's inner workings, protecting data integrity.
A constructor is a special method used to assign initial values to an object's properties during instantiation.
Inheritance allows a class to derive methods and properties from another class, creating a hierarchy of classes.
A base class is at the start of the inheritance hierarchy, while subclasses derive from it.
Polymorphism enables a class to implement an inherited method in its own way, allowing different behaviors for different subclasses.
The concept of polymorphism allows for the same interface to be implemented differently across subclasses.
Encapsulation ensures that the data and operations within an object are safe from outside interference.
Inheritance can be extended to create more specific types, such as an employee or customer class inheriting from a person class.
A class library is a collection of classes that can be used by other software developers, protecting intellectual property.
The interface of a class is all that is needed for a programmer to use its objects, hiding the implementation details.
Polymorphism literally means 'many forms', allowing objects of the same type to behave differently.
Object-oriented programming concepts enable the creation of flexible and reusable software components.
Transcripts
the four fundamental concepts
of object-oriented programming are
abstraction encapsulation inheritance
and polymorphism before considering what
they mean
first consider what is an object
an object is a thing from the real world
it could be a car a boat or a book
but it might not be something physical
that you can touch
it could be a dental appointment a seat
reservation for the cinema
or a bank account in the realm of object
object-oriented programming
an object is anything of interest to the
software application that you're
building
it's anything that you want to store and
process
data about another name for an object
is an entity
this leads us to the first fundamental
concept
of object-oriented programming namely
abstraction abstraction means to
simplify reality
for example a person is an object
but if you were designing a new
application to process data
about a person it's unlikely that you'd
be interested
in everything there is to know about a
person
rather you would only concern yourself
with the data
that are relevant and the tasks that you
want to perform with those data
to create objects programmatically you
need
a class a class is a template for
creating objects
a class is code written by a programmer
to define the attributes
and the operations of an object
attributes describe the object
they're sometimes referred to as fields
because they contain data
most programmers know them as properties
properties are coded within the class
either as public variables or as
property procedures
operations are actions that can be done
to
or performed by the object they're
sometimes referred to as behaviors
but more commonly they're known as
methods
methods are programs within the class
that are coded either as procedures
or functions a class is a template
for creating objects and it's often
compared with a pastry cutter
because once it's been written it can be
used to create many objects
of the same type in fact a class is
sometimes referred to
as a type each object
is an instance of a class in the
computer's memory
creating an object from a class is
therefore known as
instantiation once these objects have
been created
their properties can be assigned values
making each object of the same type
a unique entity each property is defined
in the class by a property procedure
which may include code to validate a
property value
while it's being assigned this helps to
ensure the integrity of the data
contained within the object
the property values that have been
assigned to an object are collectively
known as
the state of the object
it's also possible to assign values to
properties
while an object is being instantiated by
means of a special method called new
this method is known as the constructor
the second fundamental concept of
object-oriented programming
is encapsulation this means to hide the
complexity of the inner workings of an
object
from the programs and the programmers
that make use of it it's often referred
to as
information hiding because the data
contained within an object
and the functions that manipulate the
data are bound together
and therefore safe from outside
interference
in some big software development
projects
it's common for more experienced
programmers to write the classes
that will be used by the junior
programmers
a class might be made available in the
form of a class
library indeed some software development
companies
specialise in developing new classes to
be used by
other software developers compiled class
libraries protect
their intellectual property
to write code that will create an object
from a class
then set its properties and call its
methods it's not
necessary to understand the inner
workings of the class
all the programmer needs to know is the
name of the class
the properties and methods available and
any data that need to be supplied when
they're called
in other words all our programmer really
needs to know about
is the interface of the class the
implementation code of those properties
and methods
can remain a mystery this greatly
simplifies the use of objects
and helps to ensure that the data and
operations encapsulated within
are safe
the third fundamental concept of
object-oriented programming
is inheritance this means that a class
can derive its methods and properties
from another class inheritance can
result in a hierarchy of classes
for example this person class defines
the methods and properties
of a person object
an employee in a business is also a
person
so through inheritance an employee class
derives the methods and properties of
the person class
an employee is a type of person
a customer of the business is also a
person
so through inheritance a customer class
also derives the methods and properties
of the person class
a customer is a type of person
an employee class can have some extra
properties and methods of its own
it can extend the person class
and so can a customer
but it need not stop there a programmer
is a type of employee and so is a
manager
and a cleaner inheritance defines
type of relationships
the class at the start of the
inheritance hierarchy is called
the base class any class that derives
from another class
is called a sub class any class that is
derived from
is called a superclass
the final fundamental concept of
object-oriented programming
is polymorphism polymorphism
means that a class can implement an
inherited method
in its own way the person class at the
base of this hierarchy
has a method which will save details of
any object
created from the person class perhaps to
a database
thanks to inheritance all of the classes
in this hierarchy
do exactly the same thing but
it may be necessary for a customer's
details
to be saved differently perhaps to a
different database
polymorphism allows for this the
customer class can
override the workings of any method or
property
that it inherits with a new version of
its own
different forms of the same type of
object with the same
interface can behave in different ways
polymorphism literally means many forms
to recap the fundamental concepts of
object-oriented programming
abstraction means to simplify reality
and focus only on the data and processes
that are relevant to the application
being built
encapsulation means that data and the
programs that manipulate those data
are bound together and their complexity
is hidden
inheritance means that a class can
derive its methods and properties
from another class this might result in
an extensive hierarchy
of superclasses and subclasses
polymorphism means that different
subclasses
of the same superclass which therefore
share the same interface
can implement those interfaces in their
own ways
by overriding the code of the methods
they inherit
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