object oriented programming language in c++

C++ Evolution
 The prime purpose of C++ programming was to add object
orientation to the C programming language, which is in
itself one of the most powerful programming languages.
 C++ is regarded as a middle-level language, as it
comprises a combination of both high-level and low-level
language features.
 C++ was developed by Bjarne Stroustrup starting in 1979 at
Bell Labs in Murray Hill, New Jersey, as an enhancement to
the C language and originally named C with Classes but
later it was renamed C++ in 1983.
 C++ is a superset of C, and that virtually any legal C
program is a legal C++ program.

Procedure-oriented Programming
Some Characteristics exhibited by procedure-oriented
programming are:
• Emphasis is on doing things (algorithms).
• Large programs are divided into smaller programs known
as functions.
• Most of the functions share global data.
• Data move openly around the system from function to
function.
• Functions transform data from one form to another.
• Employs top-down approach in program design.

Object Oriented Programming
Some of the features of object oriented programming are:
 Emphasis is on data rather than procedure
 Element in the program development and does not allow it
to flow freely around the system
 OOP allows decomposition of a problem into a number of
entities called objects and then builds data and function
around these
 Programs are divided into what are known as objects
 Functions that operate on the data of an object are ties
together in the data structure.
 Data is hidden and cannot be accessed by external
function.
 Objects may communicate with each other through
function.
 Follows bottom-up approach in program design.

Basic Concepts of Object Oriented
Programming
These include:
 Objects
 Classes
 Data abstraction and encapsulation
 Inheritance
 Polymorphism

Objects
 An object is a software bundle of related state and
behavior.
 Software objects are often used to model the real-
world objects that you find in everyday life.
 That is both data and function that operate on data are
bundled as a unit called as object.
 Objects are the basic run time entities in an object-
oriented system. They may represent a person, a place,
a bank account, a table of data or any item that the
program has to handle. They may also represent user-
defined data such as time and lists.

Organization of Data and Function

Class
 A class is a blueprint or prototype from which objects
are created.
 Models the state and behavior of a real-world object.
 This doesn't actually define any data, but it does define
what the class name means, that is, what an object of
the class will consist of and what operations can be
performed on such an object.
 In fact, objects are variables of the type class.
 For examples, Mango, Apple and orange members of
class fruit.

Abstraction
 Data abstraction refers to, providing only essential
information to the outside word and hiding their
background details, i.e., to represent the needed
information in program without presenting the
details.
 Classes use the concept of abstraction and are defined
as a list of abstract attributes such as size, wait, and
cost, and function operate on these attributes.
 The attributes are some time called data members
because they hold information. The functions that
operate on these data are sometimes called methods or
member function.

Encapsulation
 Encapsulation is placing the data and the functions
that work on that data in the same place. While
working with procedural languages, it is not always
clear which functions work on which variables but
object-oriented programming provides you framework
to place the data and the relevant functions together in
the same object.

Inheritance
 One of the most useful aspects of object-oriented
programming is code reusability. As the name suggests
Inheritance is the process of forming a new class from
an existing class that is from the existing class called as
base class, new class is formed called as derived class.
 This is a very important concept of object-oriented
programming since this feature helps to reduce the
code size

Polymorphism
 Polymorphism, a Greek term, means the ability to take
more than on form.
 The ability to use an operator or function in different
ways in other words giving different meaning to the
operators or functions is called polymorphism. Poly
refers to many. That is a single function or an operator
functioning in many ways different upon the usage is
called polymorphism.

 The process of making an operator to exhibit different
behaviors in different instances is known as operator
overloading
 Single function name can be used to handle different
number and different types of argument. This is
something similar to a particular word having several
different meanings depending upon the context. Using
a single function name to perform different type of
task is known as function overloading.

Benefits of OOP
 Through inheritance, we can eliminate redundant
code extend the use of existing Classes
 We can build programs from the standard working
modules that communicate with one another, rather
than having to start writing the code from scratch.
This leads to saving of development time and higher
productivity
 The principle of data hiding helps the programmer to
build secure program that can not be invaded by code
in other parts of a programs

 It is easy to partition the work in a project based on
objects.
 Object-oriented system can be easily upgraded from
small to large system.
 Software complexity can be easily managed.

Application of OOP
 Real-time system
 Simulation and modeling
 Object-oriented data bases
 AI and expert systems
 Neural networks and parallel programming
 Decision support and office automation systems
 CIM/CAM/CAD systems

#include<iostream>
using namespace std;
int main()
{
cout << “ C++ is better than C.n”; // C++ statement
return 0;
}
A Simple Program
Printing a Line of Text on the Screen

#include<iostream>
 The #include directive instructs the compiler to
include the contents of the file enclosed within
angular brackets into the source file.
 Contains declarations for the identifier cout and
operator <<
 The header file iostream should be included at the
beginning of all programs that use input/output
statements.

 Namespace is a new concept introduced by the ANSI
C++ standards committee.
 This defines a scope for the identifiers that are used in
a program.
 Namespace: a naming context to distinguish between
different items with the same name
 C++ namespace: contains classes, variables, constants,
functions, etc.
 For using the identifier defined in the namespace
scope we must include the using directive
 Here, std is the namespace where ANSI C++ standard
class libraries are defined.

cout << “ C++ is better than C.n”;
 Causes the string in quotation marks to be displayed
on the screen.
 This statement introduces two new C++ features,
1. cout
2. <<
 The identifier cout is a predefined object that
represents the standard output stream in C++.
 The operator << is called the insertion or put to
operator.

Comments
// C++ statement
 C++ introduces a new comment symbol // (double
slash).
 The double slash comment is basically a single line
comment. Multiline comments can be written as
follows:
// This is an example of
// C++ program to illustrate
// some of its features

 The C comment symbols /*,*/ are still valid and are
more suitable for multiline comments. The following
comment is allowed:
/* This is an example of
C++ program to illustrate
some of its features
*/

AVERAGE OF TWO NUMBERS
#include<iostream> // include header file
int main()
{
float number1, number2, sum, average;
cout << “Enter two numbers:”;
cin >> number1; // Read Numbers
cin >> number2; // from keyboard
sum = number1 + number2;
average = sum/2;
cout << ”Sum = “ << sum << “n”;
cout << “Average = “ << average << “n”;
return 0;
} //end of example

The output would be:
Enter two numbers: 6.5 7.5
Sum = 14
Average = 7

cin >> number1
 Is an input statement and causes the program to wait
for the user to type in a number. The number keyed in
is placed in the variable number1.
 The operator >> is known as extraction or get from
operator.

cout << ”Sum = “ << sum << “n”;
Cascading of I/O Operators
 The statement First sends the string “Sum = “ to cout and
then sends the value of sum. Finally, it sends the newline
character so that the next output will be in the new line.
Using the cascading technique, the last two statements can
be combined as follows:
1. Cout << “Sum = “ << sum << “n”
<< “Average = “ << average << “n”;
2. Cout << “Sum = “ << sum << “,”
<< “Average = “ << average << “n”;
 We can also cascade input operator >> as shown below:
Cin >> number1 >> number2;

Example with Class
 One of the major features of C++ is classes. They provide a method of binding
together data and functions which operate on them.
#include<iostream> // include header file
class person
{
char name[30];
Int age;
public:
void getdata(void);
void display(void);
};
void person :: getdata(void)
{
cout << “Enter name: “;
cin >> name;
cout << “Enter age: “;
cin >> age;

Void person : : display(void)
{
cout << “nNameame: “ << name;
cout << “nAge: “ << age;
}
Int main()
{
person p;
p.getdata();
p.display();
Return 0;
} //end of example
The output of program is:
Enter Name: Ravinder
Enter age:30
Name:Ravinder
Age: 30

object oriented programming language in c++

Recommended

More Related Content

Similar to object oriented programming language in c++ (20)

Recently uploaded (20)

object oriented programming language in c++