Oops concepts
Object
Oriented Programming (OOP) is a programming model where programs are
organized around objects and data rather than action and logic.
OOP allows decomposition of a problem into a number of entities called objects and then builds data and functions around these objects.
OOP allows decomposition of a problem into a number of entities called objects and then builds data and functions around these objects.
- The software is divided into a number of small units called objects. The data and functions are built around these objects.
- The data of the objects can be accessed only by the functions associated with that object.
- The functions of one object can access the functions of another object.
OOP
has the following important features.
Class
Class
A
class is the core of any modern Object Oriented Programming language such as
C#.
In
OOP languages it is mandatory to create a class for representing
data.
A
class is a blueprint of an object that contains variables for storing data and
functions to perform operations on the data.
A
class will not occupy any memory space and hence it is only a logical
representation of data.
To
create a class, you simply use the keyword "class" followed by the
class name:
class
Employee
{
}
Object
Objects are the basic run-time entities of an object oriented system. They may represent a person, a place or any item that the program must handle.
"An object is a software bundle of related variable and methods."
"An object is an instance of a class"
{
}
Object
Objects are the basic run-time entities of an object oriented system. They may represent a person, a place or any item that the program must handle.
"An object is a software bundle of related variable and methods."
"An object is an instance of a class"
A
class will not occupy any memory space. Hence to work with the data represented
by the class you must create a variable for the class, that is called an
object.
When
an object is created using the new operator, memory is allocated for the
class in the heap, the object is called an instance and its starting address
will be stored in the object in stack memory.
When
an object is created without the new operator, memory will not be allocated in
the heap, in other words an instance will not be created and the object in the
stack contains the value null.
When
an object contains null, then it is not possible to access the members of the
class using that object.
class Employee
{
}
class Employee
{
}
Syntax
to create an object of class Employee:
Employee objEmp = new Employee();
All the programming languages supporting Object Oriented Programming will be supporting these three main concepts:
Employee objEmp = new Employee();
All the programming languages supporting Object Oriented Programming will be supporting these three main concepts:
- Encapsulation
- Inheritance
- Polymorphism