Oop(object oriented programming)

1
Object-Oriented
Programming(OOP)

2
Paradigm Shift in Programming
Programs: Data, Statements, Functions
Programming with flowchart
Program = Data Structure + Algorithms
Structured Programming
– Sequence Instructions
– Decision Making
– Looping

ALGORITHMS
• An algorithm is a sequence of precise instructions for
solving a problem in a finite amount of time.
Properties of an Algorithm:
• It must be precise and unambiguous(accurate
meaning)
• It must give the correct solution in all cases
• It must eventually end.

Understanding the Algorithm
• Possibly the simplest and easiest method to
understand the steps in an algorithm, is by
using the flowchart method. This algorithm is
composed of block symbols to represent each
step in the solution process as well as the
directed paths of each step. (Pictorial
Representation of an Algorithm)

The most common block symbols are:

Problem for Flowchart
• A variable is a symbolic name assigned to a
computer memory which stores a particular
value.
e.g. COUNTER, SUM, AVE
Calculate its Average ?

A flowchart representation of the algorithm
for the above problem can be as follows:

8
History of Object-Oriented ProgrammingHistory of Object-Oriented Programming
 SIMULA ISIMULA I (1962-65) and(1962-65) and SIMULA 67SIMULA 67 (1967) were the(1967) were the
first two object-oriented languages.first two object-oriented languages.
 Developed at the Norwegian Computing Center,Developed at the Norwegian Computing Center,
Oslo, Norway by Ole-Johan Dahl and KristenOslo, Norway by Ole-Johan Dahl and Kristen
Nygaard .Nygaard .
 Simula 67 introduced most of the key concepts ofSimula 67 introduced most of the key concepts of
object-oriented programming: objects and classes,object-oriented programming: objects and classes,
subclasses (“inheritance”), virtual procedures.subclasses (“inheritance”), virtual procedures.

9
Object-Oriented Programming
• Programming for simulation
• Software Crisis
• Software Reuse
• Software IC
• Polymorphism,Inheritance and Encapsulation (PIE).
• Classes as an Abstract Data Type(Abstraction)
• Easy to debug and maintain
• Mainstream in software development
• Software components.

Object Oriented Languages
• Eiffel (B. Meyer)
• CLOS (D. Bobrow, G. Kiczales)
• SELF (D. Ungar et al.)
• Java (J. Gosling et al.)
• BETA (B. Bruun-Kristensen, O. Lehrmann Madsen, B.
Møller-Pedersen, K. Nygaard)
• Other languages add object dialects, such as
TurboPascal
• C++ (Bjarne Stroustrup)

Structured Programming
Concept(Modular Prog.)
Structured programming techniques assist the
programmer in writing effective error free
programs.
Top down approach
Overall program structure divided into
separate subsections
This technique help to make isolated small
pieces of code easier to understand without
having to understand the whole program at
once.

Cont….
After a piece has been tested and studied in
detail individually, it is than integrated into
the overall program structure.
It is possible to write any computer program
by using only three (3) basic control structures
(logical concept’s) :
– Sequence instructions
– Decision Structure(if-else)
– Loop (While, Do While,…)
Ex. are Pascal , C, ADA.

Procedural ProgrammingProcedural Programming
(Procedure oriented)(Procedure oriented)
 Top down approachTop down approach
 Procedures, also known as functions or methodsProcedures, also known as functions or methods
simply contains a series ofsimply contains a series of
computational(Algorithmic) steps to be carriedcomputational(Algorithmic) steps to be carried
out.out.
 procedural programming specify the syntax andprocedural programming specify the syntax and
procedure to write a program.procedure to write a program.
 Big program is a divided into small pieces.Big program is a divided into small pieces.
 Functions are more important than data.Functions are more important than data.
 Input- arguments, output-return values.Input- arguments, output-return values.
 Ex. are C, Algol etc.Ex. are C, Algol etc.

Top down approach
 A complex program divides into smaller
pieces, makes efficient and easy to
understand a program.
Begins from the top level.
Emphasize the planning and complete
understanding of a program
No coding can begins until a sufficient level of
module details has been reached.

Advantages of the Top-Down
Design Method
• It is easier to comprehend the solution of a smaller and less
complicated problem than to grasp the solution of a large and
complex problem.
• It is easier to test segments of solutions, rather than the
entire solution at once. This method allows one to test the
solution of each sub-problem separately until the entire
solution has been tested.
• It is often possible to simplify the logical steps of each sub-
problem, so that when taken as a whole, the entire solution
has less complex logic and hence easier to develop.
• A simplified solution takes less time to develop and will be
more readable.
• The program will be easier to maintain.

Bottom up approach
Reverse top down approach.
 Lower level tasks are first carried out and are
then integrated to provide the solution of a
single program.
Lower level structures of the program are
evolved first then higher level structures are
created.
It promotes code reuse.
It may allow unit testing.

Concept of Class and ObjectConcept of Class and Object
 ““ClassClass” refers to a blueprint. It defines the variables and” refers to a blueprint. It defines the variables and
methods the objects support. It is the basic unit ofmethods the objects support. It is the basic unit of
Encapsulation. It also defines as the Collection of aEncapsulation. It also defines as the Collection of a
similar types of objects.similar types of objects.
 ““ObjectObject” is an instance(Properties) of a class. Each” is an instance(Properties) of a class. Each
object has a class which defines its data and behavior.object has a class which defines its data and behavior.

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Structure of a Class in C++Structure of a Class in C++
class name {
declarations
constructor definition(s)
method definitions
}
attributes and
symbolic constants
how to create and
initialize objects
how to manipulate
the state of objects
These parts of a class can
actually be in any order

Sample classSample class
#include<iostream.h>#include<iostream.h>
class Pencilclass Pencil
{{
public String color = “red”;public String color = “red”;
public int length;public int length;
public float diameter;public float diameter;
setcolor(string);setcolor(string);
public void setColor (Stringpublic void setColor (String
newColor) {newColor) {
color = yellow;color = yellow;
}}
}}

private: private members are
accessible
only in the class itself.
protected: protected members are
accessible in classes in the
same package, in
subclasses of the class and
inside the class.
public: public members are
accessible anywhere
(outside the class).
Members of class

Features of OOP
Polymorphism
Inheritance
Encapsulation
(PIE)

Polymorphism
“Poly”= Many, “Morphism”= forms
For ex. We want to find out max. out of three
no., We can pass integer, float etc.
Two types –
 Compile time polymorphism.
 Run time polymorphism.

Polymorphism
World
India China USA
Rajasthan New delhi Washington New york

Inheritance
 Mechanism of deriving a new class from an
already existing class.
5 types of inheritance
 Single level
 Multilevel
 Multiple
 Hierarchical
 Hybrid

Base classFlower
Rose
Rajasthan
Jaipur
World
IndiaDerived class
Single level
Multi levelBird
Parrot Sparrow
Multiple
Base class
Derived class

Class A
{
};
Class B:public A
{
};
Class C:public B
{
};
Class D: public C
{
};
Multi level
Class AClass A
{{
};};
Class BClass B
{{
};};
Class C:public A, Public BClass C:public A, Public B
{{
};};
MultipleMultiple
Class baseClass base
{{
Data members andData members and
Functions;Functions;
};};
ClassClass
derived:public basederived:public base
{{
Data members andData members and
functions;functions;
};};
Single LevelSingle Level

Hierarchical Inheritance
A
B C D
E F IHG J

I Half(Hierarchical)
Class D
Class B Class C
Class A
Class CClass B
Class D
Class B Class C
Class A
II Half (Multiple )
Hybrid
Hybrid = Hierarchical + Multiple
Class D
Class A
Class B Class C
Hybrid = Multi level+ Multiple

Ex. of Inheritance
RTU
Engg. college
ECE Deptt.EE Deptt.CS Deptt. Civil Deptt.
Parent class
Child class
Sub classes of child class

PPP INHERITANCE
(CLASS MEMBERS)
 PUBLIC :
Class B: public A
{
};
** the line class B: public A tells the compiler that we are
inheriting class A in class B in public mode. In public mode
inheritance note the followings:
a. all the public members of class A becomes public members
of class b
b. All the protected members of class A becomes protected
members of class B
c. Private members are never inherited.

Encapsulation
Encapsulation is the mechanism that binds
the data & function in one form known as
class. The data & function may be private or
public.

Animal
Dog Cat Fish
Mutt Poodle Gold Beta
Objects binds together in form of
a Class…

“Bjarne Stroustrup”
develops C++ (1980’s)
Brings object oriented
concepts into the C
programming language

34
Why Reading Language C++ ?
• As a better C
• As an Object-Oriented Programming Language
• Faster than other OO Languages
• It derives using the increment (++) operator of
C, because it have some advanced features of
C.

C++ Character set
A – Z= 26 = 65 to 90
a – z = 26 = 97 to 122
0 – 9 = 10 = 48 to 57
Symbols = 34= other values
TOTAL = 96
ASCII ValuesASCII Values

C++ Data types
S. No DATA TYPE Size (in bytes) RANGE
1 Short int 2 -32768 to +32767
2 Unsigned short
int
2 0 to 65535
3 long int 4 -2147483648 to 2147483647
4 Float 4 3.4e-38 to 3.4e+38
5 Char 1 -128 to 127
6 Unsigned char 1 0 to 255
7 Unsigned long int 4 0 to 4294967295
8 Double 8 1.7e-308 to 1.7e+308
9 Long double 10 1.7e-308 to 1.7e+308

C++ Tokens
Keywords (63)
Identifiers
Constants (2)
Strings
Operators (18)
Special Symbols

C++ Constants
Non Numeric constantsNon Numeric constantsNumeric ConstantsNumeric Constants
Real ConstantsReal Constants
Integer ConstantsInteger Constants
String ConstantsString Constants
Character ConstantsCharacter Constants
Decimal, Octal, HexDecimal, Octal, Hex

C++ Operators
S. No OPERATORS SYMBOLS
1. Arithmetic +,-,/,*,%
2. Logical &&,||,!
3. Relational <,>,>=,<=,==,!=
4. Assignment =
5. Increment ++
6. Decrement --
7. Comma ,
8. Conditional (Ternary) ?:
9. Bitwise &,|,^,!,>>,<<
10. Special Operator Sizeof
11. Extraction >>
12. Insertion <<
13. Dynamic Memory Allocator New
14. Dynamic memory De-allocator Delete

41
Some streams in<iostream.h>
• cout
• cin
• Operator << (Insertion)
• Operator >> (Extraction)
• endl

C vs C++
C Program
#include<stdio.h>
void main()
{
int a;
printf (“ Enter the value ”);
scanf(“%d”, &a);
printf(“n a=%d”,a);
}
C++ Program
#include<iostream.h>
void main()
{
int a;
cout<<“Enter the value”;
cin>>a;
cout<<endl<<“a=”<<a;
}

43
Program Hello
// This program outputs the message
// Hello! to the screen
#include <iostream.h>
void main()
{
cout <<"Hello!"<< endl;
}

44
Stream Input/Output
Keyboard
Console Unit
INDIA
INDIA
Stream Input
Stream Output

45
Program Average
void main() {
int x;
int y;
cout <<"Enter two numbers n";
cin >> x >> y;
cout <<"Their average is: ";
cout << (x + y)/2.0 << endl;
}

46
Structures
Void main() {
struct book{
int page_no;
char name[15];
};
book b1;
b1.page_no=125;
b1.name =“oops”;
cout <<“Book Name"<< b1.name <<“Book
page no"<< b1.page_no <<endl; }

47
Call by Reference
#include<conio.h>
void swap(int *, int *);
void main() {
int i=7, j=-3;
Clrscr();
swap(&i,&j);
cout <<"i = "<< i << endl
<<"j = "<< j << endl;
getch();
}
void swap(int *a, int *b) {
int t;
t = *a;
*a = *b;
*b = t;

48
Return by reference
• Example
int val1() {
//……
return i;
}
//……
j = val1();
i j
Temporary
storage
8 8 8

Matrix Multiplication
#include<conio.h>
void main()
{
int row1,col1,row2,col2;
int i,j,k;
int mat1[5][5],mat2[5][5],multi[5][5];
clrscr();
cout<<"enter the row for first matrixn";

cin>>row1;
cout<<"enter column for first matrixn";
cin>>col1;
cout<<"enter elements of first matrixn";
for(i=0;i<row1;i++)
{
for(j=0;j<col1;j++)
{
cin>>mat1[i][j];
}
}
cout<<"enter the row of second matrixn";
cin>>row2;
cout<<"enter column for second matrixn";
cin>>col2;
cout<<"enter elements of second matrixn";

for(i=0;i<row2;i++)
{
for(j=0;j<col2;j++)
{
cin>>mat2[i][j];
}
}
if(col1==row2)
{
cout<<"multiplication of matrices isn";
for(i=0;i<row1;i++)
{
for(j=0;j<col1;j++)
{

multi[i][j]=0;
for(k=0;k<col1;k++)
{
multi[i][j]+=mat1[i][k]*mat2[k][j];
}
cout<<multi[i][j];
}
cout<<endl;
}
}
else
cout<<"multiplication is not compatible";
getch();
}

53
Inline Functions
inline void swap(int&, int&);
int main() {
int i=7, j=-3;
swap(i,j);
cout <<"i = "<< i << endl
<<"j = "<< j << endl;
return 0;
}
void swap(int& a, int& b) {
int t;
t = a;
a = b;
b = t;
}

Overloading
A class can have more than one method with the
same name as long as they have different parameter
list.
public class Pencil
{
public void setPrice (float
newPrice) {
price = newPrice;
}
public void setPrice (Pencil p) {
price = p.getPrice();
}

Oop(object oriented programming)

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