OOP Concepts

 

 OOPS(Object Oriented Programming System)
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Languages like c,pascal,fortran,cobol etc.. are called procedure oriented languages.Because they follow procedure oriented approach.
Languages like c++,java are called object oriented languages.Because they follow object oriented approach.

IIQ)what is SRS(software requirements specification)?
SRS is report that contains client requirements and strategies to fulfill those requirements.

IIQ)What is SDS(software design specification)?
It is a report that contains IO streams(input/output),TSUODO code(logic to convert i/p to o/p),DFD's(data flow diagram),Database description etc..,

==>In procedure oriented approach programmer concentrates only on the problem and its solution.We need another approach where the entire behaviour of the system is studied and then only the software is developed.

==>Prodcedure oriented approach is suitable for handling small projects(less than 1,00,000 lines).We need another approach where the programmer will have better control even though lacks of lines of code is there.

==>programming in procedure oriented approach is un natural.We need another approach where programming reflects human beings life.

Because of the above reasons a new approach (or) methodology is created or developed it is calld OOPS.
                                

Object:-
It is any thing that exists physically in this world.

=>An object has properties and actions.
=>Properties are represented by variables.
=>Actions are represented by methods.
=>An object contains variables and methods.
                                             

Class:-
A class is a group name that specifies properties and actions       of objects.

=>class also contains properties and actions.It means a class also    contains variables and methods.
=>class does not exist physically.=>An object is an instance(physically happining) of a class.
=>A class is an idea (blue print or model) for creating objects.
=>An object does not exist without a class.But a class can exist with    out any object( ex:= dynocerous)
                                   

Encapsulation:-
Taking data and code as a single unit is called encapsulation.
ex:- class.
The members of one class is isolated from the members of another class.So the programmer can use same names for the members of two different classes.

                                        

Abstraction:- (hiding)
Un neccessary data is hiding from the user.
It is implemented using the keywords like private,public etc.., They are called access specifiers.
                                        

Inheritance:-
Producing new classes based on existing classes is called      inheritance.
   Advantage of inheritance is re-usability.
                        

Polymorphism:-
This word comming from two greek words.
poly = many  and morphos=forms.
The ability to exist various forms is nothing but          polymorphism.

=> if a variable (or) object (or) method performs different tasks is    called polymorphism.

IIQ)what is difference between object oriented programming and object      based programming?
OOP languages follow all the features of OOPS.
ex:- c++,java,simula67,smalltalk etc..
Object based programming languages follow all the features of         OOPS except inheritance.
ex:- javascript,vbscript.