Basic Features Of Object oriented

Posted: October 17, 2012 in Object Oriented concept Via C#

OK !! So we have decided to learn Object Oriented concepts and in my last blog i discuss about object-oriented methodology.

If you’ve never used an object-oriented programming language before, you’ll need to learn a few basic concepts before you can begin writing any code. This particular blog will introduce you to objects, classes, inheritance, interfaces, and packages. Each discussion focuses on how these concepts relate to the real world. So HERE WE GO !!

  •  Inheritance :Creating a new class from existing class is called as inheritance. 

        //All the car properties can be used by the supercar

    class SuperCar : car

    {

    }

    When a new class needs same members as an existing class, then instead of creating those members again in new class, the new class can be created from existing class, which is called as inheritance.

    Main advantage of inheritance is reusability of the code.

    During inheritance, the class that is inherited is called as base class and the class that does the inheritance is called as derived class and every non private member in base class will become the member of derived class.

http://msdn.microsoft.com/en-us/library/ms173149.aspx

follow this link to understand more about inheritance.

Encapsulation: in the context of C#, refers to an object’s ability to hide data and behavior that are not necessary to its user. Encapsulation enables a group of properties, methods and other members to be considered a single unit or object.

The following are the benefits of encapsulation:

  • Protection of data from accidental corruption
  • Specification of the accessibility of each of the members of a class to the code outside the class
  • Flexibility and extensibility of the code and reduction in complexity
  • Lower coupling between objects and hence improvement in code maintainability

Encapsulation is used to restrict access to the members of a class so as to prevent the user of a given class from manipulating objects in ways that are not intended by the designer. While encapsulation hides the internal implementation of the functionalities of class without affecting the overall functioning of the system, it allows the class to service a request for functionality and add or modify its internal structure (data or methods) to suit changing requirements.

Encapsulation is also known as information hiding.

Encapsulation in C# is implemented with different levels of access to object data that can be specified using the following access modifiers:

  • Public: Access to all code in the program
  • Private: Access to only members of the same class
  • Protected: Access to members of same class and its derived classes
  • Internal: Access to current assembly
  • Protected Internal: Access to current assembly and types derived from containing class

Encapsulation can be illustrated with an example of an Employee object that stores details of that object. By using encapsulation, the Employee object can expose the data (like Name, EmployeeID, etc.) and methods (like GetSalary) necessary for using the object, while hiding its irrelevant fields and methods from other objects. It’s easy to see a situation in which all users could access basic information about an employee while restricting salary information.

Abstraction:Abstraction is another good feature of OOPS. Abstraction means to show only the necessary details to the client of the object. Do you know the inner details of the Monitor of your PC? What happen when you switch ON Monitor? Does this matter to you what is happening inside the Monitor? No Right, Important thing for you is weather Monitor is ON or NOT. When you change the gear of your vehicle are you really concern about the inner details of your vehicle engine? No but what matter to you is that Gear must get changed that’s it!! This is abstraction; show only the details which matter to the user.
Let’s say you have a method “CalculateSalary” in your Employee class, which takes EmployeeId as parameter and returns the salary of the employee for the current month as an integer value. Now if someone wants to use that method. He does not need to care about how Employee object calculates the salary? An only thing he needs to be concern is name of the method, its input parameters and format of resulting member, Right?
So abstraction says expose only the details which are concern with the user (client) of your object. So the client who is using your class need not to be aware of the inner details like how you class do the operations? He needs to know just few details. This certainly helps in reusability of the code.
As I have generally seen developers are not very much comfortable with the database programming. Let’s say you are designing a class that is used to interact with the database and to perform some of database operations. Now client of your class need not to be aware of database programming, he just need to be aware of some of the details of your class and easily can perform the database operations exposed by your class without deep knowledge of database programming.
The best thing of abstract is that this decouples the user of the object and its implementation. So now object is easy to understand and maintain also. As if there is any change in the process of some operation. You just need to change the inner details of a method, which have no impact on the client of class.

Polymorphism: It is property of the class to exhibit behavior of more than one kind.

one class behaves in many form. right !! so lets elaborate this.It allows you to invoke derived class methods through a base class reference during run-time. This is handy when you need to assign a group of objects to an array and then invoke each of their methods. They won’t necessarily have to be the same object type. However, if they’re related by inheritance, you can add them to the array as the inherited type. Then if they all share the same method name, that method of each object can be invoked. This lesson will show you how to accomplish this.

More practically i will discuss each in my next blog !!

Till then..Keep Reading !!
 

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