Introduction to OOPS

Introduction to Object Oriented Programming

Types of Programming Languages:

• Structure Oriented Programming Language:

             The  programming  implementation  flow  depends  on  structures.  That means  you  need  to create  the structures  for  each  data  entity.  Those structure members can be created in the  individual functions.

             Ex: Pascal, C, C++ etc.

• Object Oriented Programming Languages:

The  programming  implementation  flow  depends  on  classes.  In  the main()  method,  you  need  to create  the  instances  for  the  classes  and access those methods. These instances are called "Objects".

Ex: C++, VC++, Java and all .NET languages.

The "OOP" is a new type of programming style, introduced in 1980‘s.

Basic Terminology in OOP Languages:

• Class:

A class describes about the logical structure of an object. That means it describes about the data to be stored in the in an object and also some operations, that are to be performed on that data. No memory will be allocated for the class. In other words, a class is used to classify the objects.

   Syn:

          class classname

             {

                //fields

                //properties

                //methods

             }

• Field / Data Member:

A  variable,  declared  inside  of  the  class  is  called  as  "field"  / "data member". The fields are used to store the data values.

• Property:

It‘s an extension to the field, which automatically performs the specified code, whenever its value is changed.

• Method / Member function:

It‘s also called as operation / member function. A method is nothing but a function, which is defined inside of the class. It is used to perform some process on the data members.

• Object:

It‘s an instance of the class. It‘s required because, no memory will be allocated for the class, so   that 

you can‘t store any data and you can‘t call any operation. It is similar to "structure variables", which is declared for the "structure". The  actual  memory  will  be  allocated  for  the  object,  which  includes  with 

all the data members. The object can access the members that are defined in the class.

By default, the objects are isolated. That means there is no any relation between the data stored in one object and another object.