What are the oops concept

Abstraction

"Abstraction" refers to the act of representing essential features without including the background details or explanations. Classes use the concept of abstraction and are defined as a list of abstract attributes.

Real time e.g. /we invented flight based on the mechanism of Birds. So

Flight is derived from the base of birds.

For example code

 abstract class MobilePhone

 {

    public void Calling();

    public void SendSMS();

 }

public class Nokia1400 : MobilePhone

 {

 }

public class Nokia2700 : MobilePhone

 {

    public void FMRadio();

    public void MP3();

    public void Camera();

 }

public class BlackBerry : MobilePhone

 {

    public void FMRadio();

    public void MP3();

    public void Camera();

    public void Recording();

    public void ReadAndSendEmails();

 }

Encapsulation

Is the ability of an object to hide its data and methods from the rest of the world. It is one of the fundamental principles of OOPs. 

Real time

e.g. / Ink is the important component in pen but it is hiding by some other material

Say we create a class, named Calculations. This class may contain a few members in the form of properties, events, fields or methods. Once the class is created, we may instantiate the class by creating an object out of it. The object acts as an instance of this class, the members of the class are not exposed to the outer world directly; rather, they are encapsulated by the class.

For example code

Public class Calculations

{

  private void fnMultiply(int x, int y)

  {

  return x * y;

  }

}

...

...

Calculations obj;

int Result;

Result = obj.fnMultiply(5,10)

Inheritance

One class properties occur from another class properties it’s called about inheritance

Real time e.g. / parent-child relation

For example code

public class Asset

{

    public string Name;

}

Next, we define classes called Stock and House, which will inherit from Asset. They

Get everything an Asset has, plus any additional members that they define:

public class House : Asset // inherits from Asset

{

    public decimal Mortgage;

}

Here’s how we can use these classes:

Stock msft = new Stock

{

  Name = "MSFT",

  SharesOwned = 1000

};

Console.WriteLine(msft.Name); // MSFT

Console.WriteLine(msft.SharesOwned); // 1000

House mansion = new House

{

  Name = "Mansion",

  Mortgage = 250000

};

Console.WriteLine(mansion.Name); // Mansion

Console.WriteLine(mansion.Mortgage); // 250000

The subclasses, Stock and House, inherit the Name property from the base class, Asset.

Polymorphism

A single function or single operator has different character

In different place.

Real time e.g. /A girl plays a role of daughter at home and a manager at

Office

For example code

References are polymorphic. This means a variable of type x can refer to an object

That subclasses x. For instance, consider the following method:

public static void Display (Asset asset)

{

  System.Console.WriteLine (asset.Name);

}

This method can display both a Stock and a House, since they are both Assets:

Stock msft = new Stock ... ;

House mansion = new House ... ;

Display (msft);

Display (mansion);

Polymorphism works on the basis that subclasses (Stock and House) have all the

features of their base class (Asset). The converse, however, is not true. If Display

was modified to accept a House, you could not pass in an Asset:

static void Main()

 {

   Display(new Asset());

 } // Compile-time error

public static void Display(House house) // Will not accept Asset

{

   System.Console.WriteLine(house.Mortgage);

}

Thanks…

Ref C# nutshell and Google