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Hello everyone so welcome to this new session.



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So we've already discussed about object oriented programming but there are a few topics that are left.



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OK.



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So let's discuss them one by one.



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OK.



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So there are some concepts self hopes they are abstraction



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and get solution



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and that are dance and polymorphism polymorphism



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OK.



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So in this we do we will try to cover these two.



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Okay.



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So we will go at these two and this will do.



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And then in the next two videos we will try to cover inheritance and polymorphism.



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Okay so let's start with the ancap solution.



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Okay so let's start with these encapsulation.



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So what is the meaning of encapsulation



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so the meaning of an absolution is clubbing.



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We have two club things.



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Okay.



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So combining things.



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So what we're doing encapsulation is we really combine the data and the functions data members and the



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functions okay.



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So combining that with the members and the functions of an entity is what we call encapsulation okay.



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Combining leader the members and the functions of an entity is what we call ancap solution okay.



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So we can achieve encapsulation with the help of a class.



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Okay.



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So this is nothing but a class.



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So with the help of class we can achieve encapsulation.



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Let us take an example.



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So suppose I have a student class so industrial in the class let's say the duty members let's say the



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properties are.



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I have a name.



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Name of the student age let's say I address okay and similarly



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we have functions like certain number



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and change and dress



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okay.



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So these are the data members and these are the functions okay.



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So if you will combine the data members and the functions of an entity then it is called Encapsulation.



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So here we are combining the data members and functions into a single unit.



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Okay so this is a single unit



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with the help of glass with the help of glass.



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We can achieve our goal of encapsulation Okay so now we will color abstraction.



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Okay.



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So let's see what is abstraction.



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So what is the meaning of abstraction so the meaning of abstraction is to hide hiding what we can see



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hide.



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Okay.



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So what we will do we will hide the unnecessary details.



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Okay.



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Hiding the tools which are not important from the outside world.



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Okay.



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Hide the details which are not relevant to the outside world.



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For example we have a TV.



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Okay.



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So for example let us talk about television.



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So how we will operate television we will operate TV using the remote.



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Okay.



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So with the help of remote we can perform many operations such as on and off changing channels.



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Increase volume or decrease volume.



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Okay.



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But we do not know what happens internally when you press a button.



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Okay.



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We do not know what happens and then we leave whenever we press a button.



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Okay.



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So there is no need for us to know that.



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Okay.



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It is not important for us to know what happens when we press a button.



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So there is no need for us to know what happens internally and let's have one more example let's take



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the example of a car.



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Okay so we all know how to drive a car but we do not know how a car works.



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Okay we do not need to know how a car works to drive a car.



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Okay.



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So we are hiding the properties we are hiding how a car works from the user Okay use it will simply



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come and drive the car.



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There is no need for us to know how a car works.



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Okay.



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So these are the real world example.



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Now let's seen called So what we are doing good.



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So we all know we have studied about smart yesterday about sorting.



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So we have AI and built heart function.



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So what does symbol chart function will do.



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It will take it as input and it will sort the idea accordingly.



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Okay.



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So we have this inbuilt heart function we have this inbuilt heart function.



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So internally how it works.



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I don't care.



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Okay.



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So what we will do but use every Lou it will simply call the function sort.



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And it will give daddy and that I will get started now use it doesn't care how internally this sort



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function work although we yesterday studied about heart function but there is no need for us to like.



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There is no need for us to study how a starting works.



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We can likely use this function.



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Okay so internally how it works I don't care.



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Similarly we have something called SDL it stands for standard template library.



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So what happens is we have many of your structures



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so the example of the district just like stacks.



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Q hash map and so on.



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Okay so we have many data centers inside there still.



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These data suggest I already implemented.



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Okay so many of your district chairs are already implemented in standard amplitude in standard template



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library.



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So what we will do for example if I want to create a stack I will simply write create a stack often



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Deja and the name of the stack is as OK if I want to push element inside the stack.



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I will write as not push if I want to pop element.



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I will write as dark pop Okay so I don't care how internally it works okay.



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I don't care how I intend to lead the stack is implemented in the standard template library.



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I will just use these lines and I will get a stack okay.



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So we are hiding all these things from the use it.



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So there it is called abstraction.



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So how can we achieve abstraction so we can achieve abstraction using glass.



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Okay so let's see how so let's say we have a student class inside the student class.



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I have name rule number address so we have a class student and they say this within a class we have



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three properties name number and address.



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Now what I want to do is I want to hide the rule number from the outside world.



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Okay I want to hide this property from the outside world.



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So how we will do it in the class simply we will make this property a private property.



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Okay.



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So making the properties as private properties this is called abstraction.



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Whenever we make a property private this will not be accessible to the outside world.



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Okay.



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So this thing.



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So making the properties if you make properties private then we call it abstraction.



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We are hiding the property.



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Okay.



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So we can achieve abstraction using the class.



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If someone wants to access the raw lumber it has to call a public function of this class.



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So we will create a public function of this class.



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And if user wants to access the raw number you can access the rule number with the help of the public



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functions.



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Okay.



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But this property is directly not visible to the outside world.



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Okay.



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So we are hiding this property.



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So we have discussed what is abstraction and how we can achieve it.



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Now the question is why we want to hide details okay why we want to do abstractions.



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So there are two main reasons for doing abstractions.



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And the first reason is so the first major reason is ablation or changes so what happens is if we change



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our own code then and use the code should not be affected.



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Okay.



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So if we change our own code then user code should not be affected.



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So suppose I have a start function the art function will take as input and it will sort the area.



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Okay so let's assume initially art function internally uses bubbles art Okay let's assume we know this



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is not right but let us assume initially this thought function uses bubbles art.



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So how will user call this function.



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It will write a user will call the function in this minute sort.



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And it will give the idea.



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So now after some time we realize that bubbles art is not an efficient sorting out your name it is and



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square.



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So with changes we change internally how does art how this art function work which changes the bubbles



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out in two quick art.



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Earlier we used to use bubbles art but now we are using quick art.



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Inside this art function internally.



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Okay so if I am using quick sword now so we'll use a code will be affected.



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So the output is no.



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So the answer is no use the code will not break.



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Okay.



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If user has allowed some program inside the program if you use it is using this art function and if



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I change the internal workings of this art function then user call will not be affected.



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User code will not big.



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Okay so this is the first reason why we do abstraction.



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Okay.



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So if we change our own code then use a code should not be affected.



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Now the second main reason is to avoid errors second major reason for doing a restriction is to avoid



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errors.



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So how can we avoid this using extinction.



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So suppose this art function is a public function.



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So if this is a public function what will happen.



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Anyone can come and change it.



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Okay.



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And your numbers can come and it can change the internal properties of this art function internal logic



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of this art function.



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Okay.



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So what will happen.



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User can introduce errors in our code.



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Okay.



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But you don't want those errors.



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So what do we do we will make this art function private okay.



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So what we will do we will hide the crucial properties since we will hide the crucial properties.



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User cannot come and change those properties so user cannot introduce those errors in our code.



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Okay so we should always do.



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Abstraction Okay so this is all about abstraction.



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And next to we a deal we will discuss about inheritance.



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Okay thank you.