introduction to object oriented programming

OBJECT ORIENTED
PROGRAMMING
Introduction

REFERENCE MATERIAL
 Textbook:
 C How to program by Paul Detiel and Harvey
Detial, Prentice Hall; 10th edition (March 4, 2017)
 Reference Books:
 The C++ Programming Language, 4th Edition by
Bjarne Stroustrup
 The C++ Programming Language, 4th Edition 4th
Edition by Bjarne Stroustrup, Adison-Wesley
Professional
 Jumping into C++ by Alex Allian,
Cprograming.com

WHAT IS OOP?
 Object Oriented Programming is a programming
technique in which programs are written on basis
of objects.
 Object is a collection of data and function
 Object represent a person, place or thing in real
world.
 In OOP data and all possible function on data are
grouped together.

WHAT IS OOP?
 Object Oriented Programming is a programming
style that is associated with the concept of class,
Objects and various other concepts revolving
around these two, like inheritance,
polymorphism, abstraction, encapsulation.

EXAMPLE
 A fork is an object with properties
 a number of prongs
 its size
 material (made of plastic or metal), etc.
 Behavior and functions of a fork include
 Shredding
 Squashing
 Making design
 Eating.
3

WHY OOP IS NECESSARY ?
 The OOP (Object Oriented Programming)
approach is most commonly used approach now a
days.
 OOP is being used for designing large and
complex applications.
 The earlier approaches to programming were not
that good, and there were several limitations as
well.

EVOLUTION OF OO
PROGRAMING
 These programming approaches have been
passing through revolutionary phases just like
computer hardware.
Machine
Language
Monolithic
Approach
Procedural
Approach
Structural
Approach
OOP

EVOLUTION OF OO
PROGRAMING
 Machine Language
 for designing small and simple programs
 Monolithic Programming Approach
 the program consists of sequence of statements that
modify data.
 code is duplicated each time because there is no
support for the function.
 data is not fully protected as it can be accessed from
any portion of the program.
 programming languages include ASSEMBLY and
BASIC.

EVOLUTION OF OO
PROGRAMING
 Procedural Programming Approach
 Program is divided into functions that perform a
specific task.
 Data is global and all the functions can access the
global data.
 This approach avoids repetition of code which is the
main drawback of Monolithic Approach.
 Enabled us to write larger and hundred lines of code

EVOLUTION OF OO
PROGRAMING
 Structured Programming Approach
 divide a program in functions and modules.
 The use of modules and functions makes the program
more understandable.
 It helps to write cleaner code and helps to maintain
control over each function.
 Developed for designing medium sized programs.
 The programming languages: PASCAL and C follow
this approach.

EVOLUTION OF OO
PROGRAMING
 Object Oriented Programming Approach
 The basic principal of the OOP approach is to
combine both data and functions so that both can
operate into a single unit. Such a unit is called an
Object.
 This approach secures data also.
 Now a days this approach is used mostly in
applications.
 The programming languages: C++ and JAVA follow
this approach.

OBJECT ORIENTED DESIGN
 Object-oriented design (OOD) is the process of
creating a software system or application
utilizing an object-oriented model.
 This technique permits the creation of a software
solution based on object notion.
 OOD is an implementation of the object-oriented
programming (OOP) paradigm.

 In the object-oriented design method, the system
is considered a collection of objects (i.e., entities).
 The state is shared among the objects, and each
object is responsible for its own state data.
 Similar objects form a class.
 In other words, every object belongs to a class.

 Objects
 An Object can be defined as an entity that has a state
and behavior, or in other words, anything that exists
physically in the world is called an object. It can
represent a dog, a person, a table, etc.
 An object means the combination of data and
programs, which further represent an entity.

 Classes
 Class can be defined as a blueprint of the individual
object, attribute and method.
 Method
 Function that describe behavior of class
 Attribute
 Define in class and represents state of object.

 Example of class and object

 Example of class, method and attributes

 Message
 Objects communicate by passing messages.
 Messages contain the name of the requested
operation, and any other action required to complete
the function.
 Messages are frequently implemented through
function calls.

PRINCIPALS OF OOP
 Encapsulation
 Abstraction
 Inheritance
 Polymorphism

PRINCIPALS OF OOP
 Encapsulation
 The wrapping up of data and functions together in a
single unit is known as encapsulation.
 All properties and methods of an object are kept
private and save from other object.
 Encapsulation makes the data non-accessible to the
outside world.

PRINCIPALS OF OOP
 Encapsulation

PRINCIPALS OF OOP
 Abstraction
 Abstraction helps in the data hiding process.
 It helps in displaying the essential features without
showing the details or the functionality to the user.
 It avoids unnecessary information or irrelevant
details and shows only that specific part which the
user wants to see.

PRINCIPALS OF OOP
 Abstraction

PRINCIPALS OF OOP
 Inheritance
 Inheritance is the process in which two classes have
an is-a relationship among each other and objects of
one class acquire properties and features of the other
class.
 The class which inherits the features is known as the
child class, and the class whose features it inherited
is called the parent class.
 For example, Class Vehicle is the parent class, and
Class Bus, Car, and Bike are child classes.

PRINCIPALS OF OOP
 Inheritance

PRINCIPALS OF OOP
 Polymorphism
 Polymorphism means many forms.
 It is a feature that provides a function or an operator
with more than one definition.
 It can be implemented using function overloading,
operator overload, function overriding, virtual
function.

PRINCIPALS OF OOP
 Polymorphism

OBJECT-ORIENTED PROBLEM
SOLVING APPROACH
 Object-oriented problem solving approach is very
similar to the way a human solves daily
problems. It consists of identifying objects and
how to use these objects in the correct sequence
to solve the problem.

SOLVING APPROACH
 In other words, object-oriented problem solving
can consist of designing objects whose behavior
solves a specific problem. A message to an object
causes it to perform its operations and solve its
part of the problem.

SOLVING APPROACH
 The object-oriented problem solving approach, in
general, can be divided into following steps. They
are:
1. Understanding the problem
2. Formulating a model
3. Developing an algorithm
4. Writing a subsequent program
5. Testing and improving the program
6. Evaluating the solution.

SOLVING APPROACH
 Understanding the problem
The question has asked to find the mean
of all the given grades of a student

SOLVING APPROACH
 Formulating a model
Average = grade1 + grade2 + …. + gradeN
number of records

SOLVING APPROACH
 Developing an algorithm
grades_array = grades,
sum=0
for grade in grade array
add grades -> sum
average <- sum / length(grades_array)

SOLVING APPROACH
 Writing a subsequent program
A program is written following the above
algorithm in the programming language
of choice.

SOLVING APPROACH
 Testing and improving the program
The program is tested against all kinds of
data including but not limited to corner
cases that may break the algorithm such
as the length of the array being returned
as 0.

SOLVING APPROACH
 Evaluating the solution
The solution is evaluated and checked
whether the output is correct or not.

PROS OF OOP
 Secure
 Reusability
 High productivity
 Reduce redundancy
 Low-cost development
 Easy to maintain and modify
 Allows for parallel development.

DRAWBACKS OF OOP
 Complexity
 Hardware Constraints
 Size is larger than other programs
 It required a lot of effort to create
 It is slower than other programs
 It is not suitable for some sorts of problems
 It takes time to get used to it.

introduction to object oriented programming

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