This document provides an introduction to object-oriented programming concepts using C++. It defines key OOP concepts like classes, objects, encapsulation, inheritance and polymorphism. It explains that classes define the data and behaviors of objects. Objects are instances of classes that occupy memory. Encapsulation binds data and code into a single unit, while inheritance allows classes to inherit characteristics from other classes. Polymorphism allows different objects to respond to the same message differently. The document also gives examples of classes like Animals and provides code snippets to demonstrate classes in C++.

1. 1
Object Oriented Programming
Development
By:
Anoop Gupta
SoftEra Informative
C-DAC Training
Email:
softera.informative@gmail.c
om

2. Oops ?
Object oriented programming is a
programming paradigm which uses
objects and its interactions to design
applications and computer programs.
Simula67 was the first object-oriented
programming language. Java, Python, C+
+, Visual Basic .NET and Ruby are the
most popular OOP languages today.
2

3. Oops Features ?
Class
Object
Encapsulation
Abstraction
Polymorphism
Inheritance
3

4. Class ?
Classes are user-defined (programmer-
defined) types.
Data (data members)
Functions (member functions or methods)
In other words, they are structures +
functions
Classes are logical entity which defines
behaviors and property for Object
4

5. Class
Examples -
•Animals
•Human
•Books
•Cricketer 5

6. Classes in C++
A class definition begins with the keyword
class.
The body of the class is contained within a
set of braces, { } ; (notice the semi-colon)
6
Class class_Name
{ ………
………
……..
};
Any valid identifier
Class body (data
member + methodsmethods)

7. Object ?
Object is a real time entity which exist
physically
Object occupy some space into memory
Every object have some specific property
and behavior but all objects from the
same class share common property and
behavior
7

8. Objects ?
•Animals
8

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What are we doing today?
Introduction of:
the lecturer
Objects
Basic Terminology
C++
the module

10. Object
Fruits
10

11. Abstraction ?
Abstraction is another good feature of
OOPS. Abstraction means to show only
the necessary details to the client of the
object.
Abstraction says that hide un necessary
detail from the user which are not required
them
11

12. Abstraction
Abstraction
12

13. Encapsulation
Encapsulation is a process of binding or
wrapping the data and the codes that
operates on the data into a single entity.
This keeps the data safe from outside
interface and misuse.
Encapsulation Provide data security .
13

14. Encapsulation
Encapsulation defines the access levels
for elements of that class. These access
levels define the access rights to the data,
allowing us to access the data by a
method of that particular class itself, from
aninheritance class, or even from any
other class. There are three levels of
access:
14

15. Encapsulation
– Encapsulation
15

16. Polymorphism
16

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What is Object Oriented
Programming?
An object is like a
black box.
The internal
details are
hidden.
Identifying objects and
assigning responsibilities to
these objects.
Objects communicate to
other objects by sending
messages.
Messages are received by
the methods of an object

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What is an object?
Tangible Things as a car, printer, ...
Roles as employee, boss, ...
Incidents as flight, overflow, ...
Interactions as contract, sale, ...
Specifications as colour, shape, …

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So, what are objects?
an object represents an individual,
identifiable item, unit, or entity, either real
or abstract, with a well-defined role in the
problem domain.
Or
An "object" is anything to which a concept
applies.
Etc.

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Why do we care about
objects?
Modularity - large software projects
can be split up in smaller pieces.
Reuseability - Programs can be
assembled from pre-written software
components.
Extensibility - New software
components can be written or
developed from existing ones.

21. Example: The Person class
#include<string>
#include<iostream>
class Person{
char name[20];
int yearOfBirth;
public:
void displayDetails() {
cout << name << " born in "
<< yearOfBirth << endl;
}
//...
};
private
data
public
processes

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The two parts of an object
Object = Data + Methods
or to say the same differently:
An object has the responsibility to know and
the responsibility to do.
= +

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Basic Terminology
Abstraction is the representation of the
essential features of an object. These are
‘encapsulated’ into an abstract data type.
Encapsulation is the practice of including
in an object everything it needs hidden
from other objects. The internal state is
usually not accessible by other objects.

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Basic Terminology:
Inheritance
Inheritance means that one class inherits
the characteristics of another class.
This is also called a “is a” relationship:
A car is a vehicle
A teacher is a person
A dog is an animal

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Basic Terminology:
Polymorphism
Polymorphism means “having many
forms”. It allows different objects to
respond to the same message in different
ways, the response specific to the type of
the object.
E.g. the message displayDetails() of the
Person class should give different
results when send to a Student object
(e.g. the enrolment number).

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Basic Terminology:
Aggregation
Aggregation describes a “has a”
relationship. One object is a part of
another object.
We distinguish between composite
aggregation (the composite “owns” the
part) and shared aggregation (the part is
shared by more then one composite).
A car has wheels.

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Basic Terminology:
Behaviour and Messages
The most important aspect of an object is
its behaviour (the things it can do). A
behaviour is initiated by sending a
message to the object (usually by calling
a method).

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The two steps of Object
Oriented Programming
Making Classes: Creating, extending or
reusing abstract data types.
Making Objects interact: Creating objects
from abstract data types and defining their
relationships.

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Historical Notes
C++ owes most to C.
Other ancestors are Simula67
and Algol68.
First versions of C++ in 1980 under the
name “C with classes”. Since 1983 the
name C++ is used.
1990: ANSI/ISO 9899 defines a standard
for C
1998: ISO/IEC 14882 specifies the
standard for C++
C++ 1987

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C++ and C
C is a subset of C++.
Advantages: Existing C libraries can be
used, efficient code can be generated.
But: C++ has the same caveats and
problems as C (e.g. pointer arithmetic,…).
C++ can be used both as a low level and
as a high level language.
We focus on the
high level aspects.

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C++ and Java
Java is a full object oriented language, all
code has to go into classes.
C++ - in contrast - is a hybrid language,
capable both of functional and object
oriented programming.
So, C++ is more powerful but also
more difficult to handle than Java.

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Module Outline
Introduction
The non object
oriented basics
Classes
Design Approaches
Testing
Inheritance
Aggregation
Polymorphism
Multifile Development

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Assessment Details
50% in course and 50% exam.
For more details for the in course
assignment see separate handout.

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Books
Teach Yourself C++ in 10 minutes,
J. Liberty, SAMS 1999.
C++ - How to program, Deitel & Deitel,
Prentice Hall, 2001.
Object Oriented Programming with C++,
David Parson, Letts Educational, London
1997.

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Websites
A C++ online tutorial:
http://www.cplusplus.com/doc/tutorial/
The C++ FAQ:
http://www.parashift.com/c++-faq-lite
The homepage of Bjarne Stroustrup, the
inventor of C++:
http://www.research.att.com/~bs
And many, many more!