WEBVTT 00:00.900 --> 00:08.400 Hey, in this session, we will discuss about inheritance, so inheritance allows us to create a new 00:08.400 --> 00:12.780 child clause which is based on the existing betting class. 00:13.380 --> 00:20.760 In this particular case, the child class will have all the attributes and methods of the best in class, 00:21.030 --> 00:25.260 which can be modified internally in the first class as well. 00:25.860 --> 00:27.430 So what does this mean? 00:27.870 --> 00:35.940 So here inheritance is a way to form new classes using classes that has already been defined. 00:36.270 --> 00:44.570 So let's say we have created a class person so a person will have certain attributes and methods. 00:44.850 --> 00:51.720 So let's see the attributes related to the person I name, age, address. 00:52.680 --> 00:57.880 Now, the methodology to the person would be, let's say dog, walk, eat. 00:58.380 --> 01:03.600 Now, these are Gendron methods and general attributes related to a person. 01:04.050 --> 01:14.520 Now, whenever I'm creating an employee or a doctor or an engineer in that particular case, will I 01:14.520 --> 01:21.630 be writing the method and the attributes which are pre existing again? 01:22.080 --> 01:28.650 So ideally, what I should be doing is if I don't really know about inheritance, I would be creating 01:29.190 --> 01:36.810 an employee class and my employee class will be having certain attributes, for example, name, age, 01:36.810 --> 01:43.520 address of the person, and additionally something which is specific to employees such as their employee 01:43.520 --> 01:46.770 and their salary. 01:47.010 --> 01:52.520 And the methods would be, let's say, work or travel to office, come back from office. 01:52.770 --> 01:55.140 These are something related to the employee. 01:55.530 --> 01:59.070 Now, whenever I am creating a doctor, what will happen now? 01:59.070 --> 02:05.130 The doctor will have something like diagnose, then perform a surgery. 02:05.310 --> 02:09.300 And apart from that, it will again have the ones which will probably present. 02:09.310 --> 02:09.640 Right. 02:09.840 --> 02:16.020 So, for example, name, address and eat, sleep, work, because doctors will also perform all the 02:16.080 --> 02:19.770 actions and religious rituals are performed by a person. 02:20.100 --> 02:31.080 So here what we get to see is that whatever behavior was present in a person actually comes inside or 02:32.250 --> 02:38.100 engineer or a doctor or a student or a human being, anything like any such activity. 02:38.740 --> 02:46.410 Right now what we are doing is when we are creating this specific class, such as doctor here, we are 02:46.740 --> 02:49.410 adding a few methods additionally. 02:50.400 --> 02:50.690 Right. 02:51.030 --> 02:58.510 So basically it has different methods and attributes from the parent class, the art of the present, 02:58.530 --> 03:00.240 which would be present in to the better. 03:00.510 --> 03:03.180 So I don't create these methods. 03:03.180 --> 03:05.460 Again, I just Dellec that. 03:05.460 --> 03:07.000 Okay, you are, doctor. 03:07.020 --> 03:13.620 So this class of doctor will contain all the methods which are specific to Bochner and also inherit 03:13.620 --> 03:19.890 all the methods and attributes which are already present and created when we created a person so that 03:19.890 --> 03:22.580 we don't have to create things again and again and again. 03:23.640 --> 03:24.020 Right. 03:24.480 --> 03:27.570 Similarly, even I have created a doctor. 03:27.600 --> 03:30.930 Now this doctor is actually, let's say, a neurosurgeon. 03:31.350 --> 03:38.340 So the neurosurgeon will have some more specific details and some more specific tasks which he will 03:38.340 --> 03:38.790 perform. 03:39.150 --> 03:44.750 So now this class will inherit from the person class. 03:44.760 --> 03:46.850 Also, I'm from the doctor glassless. 03:47.760 --> 03:48.140 Right. 03:48.350 --> 03:50.650 So this can create a change. 03:50.650 --> 03:56.610 So we can what we can do is whenever I'm creating a particular class, if I need something which needs 03:56.610 --> 04:01.800 to be repeated, if I need certain behaviors and attributes which are already present in some other 04:01.800 --> 04:05.510 class, I can simply inherit from that class. 04:05.610 --> 04:07.560 I mean, I inherited from that class. 04:07.560 --> 04:14.880 The class from which I am inheriting is for the best class or the better in class and the class which 04:14.880 --> 04:22.740 I am inheriting to the new class of the day and creating is called Giedd Class or derived class. 04:24.180 --> 04:29.660 OK, so this is the basic concept behind inheritance. 04:30.180 --> 04:38.860 Now let us go back and try to create this thing and implement this thing. 04:43.500 --> 04:48.600 So let us go ahead with inheritance. 04:53.700 --> 04:57.250 Now, here's what we need is we are creating a new middle class. 04:57.270 --> 05:00.780 OK, so my class is animal. 05:01.200 --> 05:03.270 Now, what does an animal do? 05:03.300 --> 05:07.020 This is my divine creator in it. 05:08.000 --> 05:16.950 OK, this is the initialization it takes self and it to 05:25.650 --> 05:27.570 create an animal created. 05:28.050 --> 05:32.280 Now, let me create another method and say this. 05:32.610 --> 05:34.070 This is animal created. 05:34.080 --> 05:37.860 Another one is say. 05:40.950 --> 05:42.420 This one is 05:47.430 --> 05:49.080 who am I? 05:49.590 --> 05:49.930 OK. 05:50.400 --> 05:53.650 And this says that this is animal. 05:54.120 --> 05:56.310 Next I am creating. 06:02.570 --> 06:02.870 E! 06:06.100 --> 06:07.540 And what does it do? 06:07.570 --> 06:14.650 It says it OK, now I'm creating another class now. 06:14.680 --> 06:18.670 This class is what this class would be, a dog class. 06:19.060 --> 06:21.130 OK, now I'm creating a dog class. 06:21.130 --> 06:23.060 Now let's create the dog class. 06:23.590 --> 06:31.990 So I said, OK, now I want this dog class to inherit these initialization. 06:32.200 --> 06:35.170 Who am I this eat from the animal class. 06:35.200 --> 06:40.390 OK, I want this to get all the stuff which is present in my animal class. 06:40.630 --> 06:44.640 It because dog is what dog is up animal. 06:44.650 --> 06:47.310 So I want those things to be already presented. 06:47.320 --> 06:48.970 I don't want to write it down again. 06:49.330 --> 06:57.640 So what I simply do is I will tell it like you need to inherit stuff from animal class. 06:58.250 --> 07:04.480 OK, now this understand when I write it inside the brackets, it's understanding that I need to inherit 07:04.480 --> 07:05.600 from this animal class. 07:06.190 --> 07:14.640 Now, in the initialization, I would say that dog has been created by, say, dog created and I'm asking 07:14.650 --> 07:15.200 where am I? 07:15.220 --> 07:20.170 So I'll tell it that, OK, this is a dog, OK? 07:20.560 --> 07:25.230 And I create another function which is bark, OK? 07:25.540 --> 07:33.010 And when it says barking, it's where it will say, well, OK, so this is what I am doing now. 07:34.900 --> 07:35.980 What have we done now? 07:35.990 --> 07:37.750 We have created an animal class. 07:38.110 --> 07:42.880 We have created a dog class in animal class we have initialization. 07:42.880 --> 07:50.680 So when an instance of animal would be created, it will say animal created, then we will create the 07:50.680 --> 07:51.310 object. 07:51.310 --> 07:53.200 I'm from on top of that object. 07:53.200 --> 07:55.260 We will then where might will say animal. 07:55.320 --> 07:57.520 Then we will ask it to eat. 07:57.760 --> 07:58.870 It will say eating. 07:59.140 --> 08:05.350 When we create an object of dog it will say dog created when we run this. 08:05.350 --> 08:09.070 Who am I from the dog object it will say dog. 08:09.310 --> 08:16.270 And when we say bark it will say OK so let us run this one. 08:16.270 --> 08:17.470 So it has been run. 08:17.830 --> 08:21.020 Now what will create will create an object of the dog. 08:21.250 --> 08:27.040 So we will see dog one is equal to dog. 08:27.670 --> 08:30.370 So we are creating an object of the dog. 08:30.370 --> 08:33.700 Plus what happens now when I run this. 08:34.000 --> 08:39.340 It says that dog created ok. 08:41.610 --> 08:46.080 See, this is dog and the same dog created. 08:46.450 --> 08:49.570 Now let's make a little slight change. 08:49.590 --> 08:51.490 OK, now what do you see? 08:51.640 --> 08:59.460 I asked that whenever you are initializing the dog, initialize the animals. 08:59.860 --> 09:02.950 So what we can see from the animal class. 09:03.600 --> 09:09.120 OK, then, because we are calling the animal Glaswegians, the animal that we were talking about, 09:09.120 --> 09:14.190 any object, then we would have referred to the object itself here. 09:14.230 --> 09:22.130 OK, so we are seeing animal dot in it and inside this we are putting. 09:22.950 --> 09:25.180 OK, now see the difference. 09:25.230 --> 09:30.890 OK, so when we done this just a moment I'll have to run this again. 09:31.590 --> 09:33.840 When we done this we animal created. 09:33.840 --> 09:34.540 Both created. 09:34.860 --> 09:36.320 Now see the difference. 09:36.330 --> 09:42.420 OK then we wrote only this in it and only this particular in it. 09:42.420 --> 09:45.150 We have not written this particular statement. 09:45.420 --> 09:49.290 It did not run the initialization of the animal flush. 09:50.220 --> 09:57.120 OK, if you want to run the initialization of the animal class also, then you will have to run the 09:57.120 --> 09:59.600 animal in here, OK? 09:59.880 --> 10:02.910 Otherwise it will run only initialization for the book. 10:03.630 --> 10:08.130 OK, now let's go for the next thing we say. 10:08.130 --> 10:09.960 Dog one dot. 10:13.840 --> 10:18.340 I OK, and she wondered, why am I so what does it say? 10:18.350 --> 10:23.900 It says Dog, OK, now why is it saying Who am I? 10:23.910 --> 10:30.590 Because it has inherited it would have inherited this particular who am I now? 10:30.590 --> 10:36.050 Because this is present here now we have overcome this. 10:36.480 --> 10:39.150 OK, now this would have came down here. 10:39.170 --> 10:40.180 Now let me do one thing. 10:40.190 --> 10:43.940 Let me just comment this week. 10:44.450 --> 10:53.930 Now, when I go this and I run this again, I run this again and I create this object again and I run. 10:53.930 --> 10:59.120 Bob wondered, who am I now I get and what do I why do I get animal? 10:59.130 --> 11:02.660 Because this is inherited. 11:02.670 --> 11:05.030 So this comes down here. 11:05.780 --> 11:10.930 So it as it is assuming that when I am running, Bob wondered why am I. 11:10.940 --> 11:13.460 Because there is nothing as women here. 11:13.700 --> 11:17.320 So it is getting the metal from the base class. 11:17.660 --> 11:27.770 But when we come this, when we actually define who am I inside the child plus then it will give preference 11:27.770 --> 11:31.240 of priority to the Who am I present in detritus. 11:31.640 --> 11:35.580 So whatever was written in this animal class actually get over it. 11:35.860 --> 11:38.930 And when we are running, who am I from the book. 11:38.930 --> 11:41.140 One that is the object of the dog class. 11:41.330 --> 11:43.760 It will run whatever is present here. 11:43.770 --> 11:46.910 So if I run this then it will say dog. 11:47.330 --> 11:52.700 OK, next, if I say let's say dog one dog 11:55.880 --> 11:59.870 eat dog I say eat. 12:00.170 --> 12:01.010 So what happens. 12:01.010 --> 12:08.000 It says eating because it has inherited this method from the parent class because it does not present. 12:08.210 --> 12:09.470 So it will run whatever it was. 12:09.470 --> 12:13.880 But as an independent class it now again same thing applies to the bark. 12:14.390 --> 12:25.430 OK, so when I say dog one don't bark, then it will say because this is a new method which we have 12:25.430 --> 12:28.250 created in the dog and that is a Gigas. 12:28.550 --> 12:30.670 So now you understand what is happening. 12:30.680 --> 12:39.080 So basically what we are doing is if we have any method which was in the best class and is not present 12:39.080 --> 12:45.830 in the jungle, then it will run whatever it is, and basically it will run that method of method from 12:45.830 --> 12:46.550 the base class. 12:46.880 --> 12:52.400 If you have over it in the method in the gym class or you have newly created the method method in the 12:52.400 --> 12:55.090 gikas, then it will run it from each class. 12:55.170 --> 12:56.410 It's as simple as that. 12:56.420 --> 12:57.500 Nothing complicated it. 12:57.900 --> 13:05.870 OK, so next thing, what we will be learning about is polymorphism. 13:05.870 --> 13:09.890 So let's talk about this in the next session.