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Heidi is a sharing satire.

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And welcome to the next Mordieu of object oriented programming in case of Cartland now in Godling we

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have some concept of object declaration and also companion objects.

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But before learning that let us first check out what is singleton in Scotland.

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Now in case of Codlin whenever we declare a clause that we're doing so far we create instance of that

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class and then access all the variables and methods but in case of Singleton we have just one instance

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of the class in the whole application.

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So once we define class as singleton then we just have one instance and that instance is just created

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by Cartland internally.

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That is we do not have any control over creating the instance of that singleton class.

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No it means that Suppose we have a class today which is declared as singleton.

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Then we cannot create the objects of this class that is there exists only one object for this class

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by default which is created by the Codlin internally.

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In simple words we can say we cannot create objects like student 1.

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STUDENT 2 and so on.

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I hope I am clear at this point.

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And now in Java they define singleton by using the keyword of static such as we have static variables

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static methods present inside the class.

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So in that case the static variables and metrics are not a part of the class.

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They are just part of class definition not the objects right.

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So in guess of Gorlin as well.

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We don't have any static keyword present but alternative to that.

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We have some object declaration and also the concept of companion objects.

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No proceeding forward in Gondolin we can not declare static variables and methods compared to Jawa.

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So we have an alternative to diked such as we can declare object and these objects are actually acting

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as a class that can contain the static variables and methods without using the keyword of static.

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Now when we declare something as object that Coquelin internally behind the curtain simply creates a

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singleton object for us when the program is running.

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So when we are in the program we get one instance of that object.

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So how do we declare the object in case of Codlin.

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So in Cartland.

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Let's check out the code snippet.

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Suppose we have object customer.

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Now here we don't have Klasky word we are using object keyword.

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So object space custom.

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This is syntax instead of.

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Suppose I have variable The other type of integer.

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Now this ID is actually acting as a static variable compared to Java.

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This is not exactly a static but behaving like a static variable like we call it static.

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In case of Java but I similarly suppose I have a function register customer.

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So this method as well is behaving as a static method.

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Now then we call a static variable and static method.

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If you are from Java background then you must be knowing how to access the static variables and methods

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not to access these variables and methods.

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We need to use simply use customer door Id like say 27.

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So here we are simply using customer.

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This customer is the name of this object or right.

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So class name or the object name dot ID equal to 27.

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That looks similar to the code snippet from the Java background.

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And next we can call customer d'arte register customer and our record inside the function will be executed

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non-nudist.

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Here we are calling without creating any instance.

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That is we don't need to declare it as the object explicitly.

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The Codlin by default creates an object instance that is a singleton instance for our customer class

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or the object so let us proceed and check out the cold inside their Damore application.

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So here inside the intelligent ID I will simply declare the class of customer.

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So here inside the intelligent ID I've simply created an automated class of customers data that contains

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the customer's account and also type of customer that simply returns a string value.

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Now in order to access discount variable and also this method inside the main we need to do these called.

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So here in order to access the count variable and this method we are simply calling the object name

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Darktown an object name dot method.

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Right.

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By simply creating the customer's data object.

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Now if I want to use this class as a singleton so what I would do is I would simply use sort of class.

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I would simply use object.

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So this object keyword simply creates a singleton object for this customers data.

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So we no longer can create the instance of this customer data manually because we can create the instance

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of the single Going to us.

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It is done automatically for you.

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So here I have to remove this at the top level code.

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And now in order to access the scanned variable what I need to do is we need to simply use copy this

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last name and pasted in Baystate here and now again paste it here.

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So here discussing variable is actually acting like a static variable.

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And also this method is acting like a static method.

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Right.

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So this is how we access the members of the object like this.

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And now if aproned legacy a print Ellen let's say customers data are gone.

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Let's see the output.

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So here in the output we get 98 right.

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So this Gounder value is currently ninety eight that we have defined here.

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Now suppose if I again change the value.

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Let's see.

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Two hundred and nine.

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And let's see what happens if we are we're into splendored.

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Now this time we get a hundred and nine.

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So the value has been updated.

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Two hundred and nine.

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So whenever you access this account and change the value it will be changed to that particular instance

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that was created by Cartland.

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Right.

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Because we don't have any name for that object.

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We are simply using the class name here.

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That is our object plus dog count and something like that.

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Similarly now the same thing applies for this method as well.

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Call it anywhere and it will be returning Indian string.

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Right.

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And now at the end this object customers data.

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And also in properties from the superclass.

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So it us define a class here.

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Let's call it my superclass.

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So here this customer data and also inherit the properties of my superclass.

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Now since this is my superclass So we need to treat it like object by using the primary constructor

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here.

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Right.

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And now let us make this class as open so actually so as to inherit all the properties and also if I

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want to inherit this my method or override this my method inside that customer's data.

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Then also they're disposable so far that to simply use the Bengie word here.

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And then simply override this function.

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My method simply or what I did now inserted is if you weren't going to call the super dark matter this

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year and now here.

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Let us spring just like this.

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And now you can notice this object is actually behaving like a class because it is actually inheriting

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all the properties of my superclass.

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So we can call it our derived class.

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And this is now acting as a superclass.

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Now what about this my method.

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How can we access this might make it so far that again inside the main method what we do is I would

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simply use customer's data Dorte my method and simply pass.

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Let's see.

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Hello.

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So this my method is now becoming the static member of this object.

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Right.

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So we can write the command line here.

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So this method is similar to this method is now acting as a static method inside this object of customer's

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data.

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And now if you create the instance of my superclass then you have to access this method here with the

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help of the object of this superclass.

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It is only behaving stocktake after all what I did inside the object customer's data.

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So let us know then the code and let's see what it prints.

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So here we get my superclass.

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Has God rendered just because of this statement.

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Superdog muttered an object customer data.

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Hello is getting printed which is present here.

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Right.

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So in this video we learn about how do we declare the object and also how can we find the alternative

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for the static variables and methods in case of Gorlin similar to what we do in Gears of Java.

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So at the end of this video and let us summarize the properties of the object so to later object we

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use the key word of object and Cartland internally creates a class.

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And also the instance an object of that particular class.

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But that object is only one Enchong we cannot create more object or instance again and these objects

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can have properties methods and also initializers.

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And now one thing I forgot to show you that inside the customer's data object we can also use the init

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block like this.

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And you can now initialize whatever you want to inside the init block.

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Right like this.

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So we can have initializers in case of object.

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And next we can not have constrictors inside the object as it makes sense because because we do not

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have any right to do so to create an instance manually and the object can also have a superclass like

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we saw in this video that is simply supports inheritance fine.

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So this was all about to object in case of Cartland.

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So that's all for this video.

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Have a nice day and get you guys in the next video.

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This is showing hard signing off.

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Thank you.