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Heidi this is really hard.

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Once again welcome to the next video.

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All this object oriented programming now in this video will we talk about Vawter abstract classes methods

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and also properties in case of Cartland.

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So the classes in case of Cartland can also be abstract in nature.

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Now what do we exactly mean by abstract.

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We will check it out shortly.

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Now the classes in case of Cartland can be abstract in nature.

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Now before going for Vardis abstraction in Gears of Codlin.

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First let me show you vort abstract classes methods and properties inside the intelligence ID street.

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And then after we will discuss all the properties of these classes and methods.

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So here are the intelligent ID.

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I have a class of person and class Indian.

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Now suppose I wanted to inherit all the properties of this class person.

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So I will simply make this class person as open as simple as that.

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This is the basic rule of the inheritance in case of Cartland.

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Now this function becomes a part of this Indian class.

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Right so this function go to school is actually is just a normal function that by default public and

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final mortified attached to it.

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So as we all know the functions are by default public and final in nature.

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So here is the command line for this.

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And now suppose inside the class of person I define one more function such as function grd the height

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of the person.

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Now this function is exactly the same as this function.

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Both are public and final in nature by default.

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Now if you wanted to override this function of get hide inside the class of Indian such as legacy override

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function Guert height then the compiler will not be happy because we have to make this function as open

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because by default it is final in nature.

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So after we make it open we can now easily override the methods inside the subclass or other derived

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class.

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Now here this Indian is actually the subclass are there derived class as we all know from the previous

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videos of concept of inheritance.

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Now notice here these methods are actually having the blank body like this.

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It is totally blank.

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So that is where the curly brackets are open and closed like this here as well it is blank.

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Right so this was a the open method and this was about this was about the final method.

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And now let us experiment more and let us define one more function of let's see function.

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Eat.

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Now this time again.

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Define a blank Bartie.

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So this function.

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It is similar to this function.

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Go to school which is again final and public by default.

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Right now I suppose if I append here let's see or even so this function it can now be overridden inside

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the class of Indian let's say override function.

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It simply override this method and you can define your own custom code inside this method right here.

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And now suppose if I change this open to let's see abstract.

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So what will happen now.

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Bideford all the abstract matters are actually open in nature.

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So you don't have to specify the open keyword explicitly.

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So let us remove it.

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So this is the abstract method.

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Now when we declare any abstract methods or a class or a property then that abstract declaration contains

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a body.

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So here this method is actually having a blank body.

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This is the blank.

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This is the body of the matter.

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Right.

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So when we declare something as abstract then that declaration should not contain any body.

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So these records should not exist.

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So let us delete it.

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So right now here is the difference between a normal function open function and an abstract function.

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So here in case of abstract we don't have any metric body.

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And again it is showing some error.

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This abstract method is actually present inside the non abstract class of person.

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So we deal with that shortly.

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So right now this method is actually abstract in nature.

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So let us define x.

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So the abstract properties are actually Bideford open by nature.

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Right.

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So it is by default we are having the open keyword so we don't have to specify that or been keyword

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again here like this.

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It is written down now before rectifying this error here inside the main method.

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Suppose if I create the instance of that class of person equal to let's say new person like this.

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So here it does not show any error.

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Now in order to rectify this error.

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Suppose this method can only exist within the abstract class.

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So here I would simply append the abstract keyword.

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But I.

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And now here again.

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By default the abstract properties classes and methods are actually by default open in nature so we

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don't have to specify open again because it is by default open by nature.

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Right now here it shows some error can cannot create an instance of an abstract classes.

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Now it is a property of an abstract class that you can not instantiate or create the objects of this

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abstract class.

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Right so the compiler will simply throw some exception here because this is not allowed to create any

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object of the abstract class.

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So here I have to remove that statement in order to rectify the error.

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Right now what is the advantage of using the abstract method such as IID.

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Now here inside the subclass of Indian I have simply overridden this method and also get height Metford

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this get height method is actually open in nature and this method is actually abstract as well as open

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in nature.

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That is very we very true do what I did here.

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Now suppose if I delete this get method from here then the compiler is still happy.

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It does not show any error because this open function get height is optional.

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We can or we cannot override that.

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Inside the Indian class it is totally up to our choice but if we remove this abstract method of it let

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us remove it.

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Then here the compiler is not happy.

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It simply says that this Indian class should override all the abstract methods and properties present

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inside the superclass of person which is again abstract in nature.

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Right.

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So if you define any abstract keyword in the superclass of person so you need to override this method

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inside the class of Indian which is a plus.

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So here to rectify this error I will simply press please enter and simply implement the members and

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simply select this method.

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And here we go.

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The intelligent ID as has simply done the job for us.

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Here we have over a function.

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And here this is there are two implementation.

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And now if you aren't you can optionally override this get method because it is only open not abstract.

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And now what about the field variables.

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Suppose if I create here that lets the name of that type of string write equal to.

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Let's see dummy underscore name.

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This is my domain name right.

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Now suppose if I want to override this property inside the class of Indian so I have to make this very

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well as often as we all are aware of this.

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Similar to what we have done here right.

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Or here for it.

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So here inside the class of Indian I will simply override the variable of name order type of string.

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And here let's see I will call dummy underscore Indian name right.

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Something like that.

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So I have simply overriding the value of name inside the subclass.

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And now the default value is the Indian name.

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Now suppose if I append abstract here and so we need to remove this open keyword because it is returned.

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Right so here now it shows some error that the abstract variable or the property cannot be instantiated.

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Now similar to method like we don't have a Metford body in case of abstract method.

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Here again we can never instantiate a property that is abstract in nature.

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So here we have to remove this equal to operator.

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So the abstract property and abstract method are just defined.

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They don't contain any code inside it.

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Right so now suppose if I come in this here so the compiler is again not happy because in the superclass

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of person we have an abstract variable name so whatever we define as an abstract we need to override

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that complexity inside the surplus.

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So if I remove this.

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And now if I press on it.

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And so here it simply shows implement members.

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So simply click on it select the name.

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They don't.

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OK.

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So by default the indelible ID has simply overridden the variable name which is of the type of string.

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Now this is their default get that sector.

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So let us remove it.

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We don't need it.

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And now here if you override a variable or the property then you need to define its body that is unique

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to initialize it.

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Let's see again dummy in your name.

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So this was all about the abstract Plus person abstract property and also abstract method.

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And now here let me add some command line.

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You can not create the instance of the abstract class for your better understanding.

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So at last later seek out the properties of the abstract class methods and also property.

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Right.

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So here the rule of abstract class is to just provide a set of methods and properties that is the abstract

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class is just off the placeholder to use it just prove why it's the set of mentors and properties without

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any value or without any body.

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So the abstract class are actually partially defined class.

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It is a class but it is partially defined right.

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It does not contain.

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It's all good.

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And next we have abstract matters which have nobody even declared.

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Right.

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And also we have abstract properties that cannot be initialized then declared.

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So previously we had this abstract matter that contains nobody.

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Again we have abstract property that contains no value.

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So are the N word.

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We can include from this value.

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So at the end we conclude that we cannot create the instance or the object of the abstract class.

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But I and we always need to override the abstract methods properties inside their derived class or supplies.

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Otherwise the compiler is sure some error.

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This is a basic rule of abstraction in case of Cartland.

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So this was all about this video.

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Hope you like 40 or so and see you guys in the next video.

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Thanks for watching.

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Have a good day.