1
00:00:00,150 --> 00:00:05,490
‫In this video, you are going to learn about inheritance in C sharp or in programming in general.

2
00:00:05,520 --> 00:00:11,220
‫I'm going to try to keep it super simple because it can become quite complicated if you look at it because

3
00:00:11,220 --> 00:00:12,180
‫there is a lot going on.

4
00:00:12,180 --> 00:00:19,560
‫But I'm going to simplify it as much as possible because the idea of inheritance is really the reusability

5
00:00:19,560 --> 00:00:20,340
‫of code.

6
00:00:20,340 --> 00:00:26,520
‫And this allows us not only to reduce our own code, but reduce code of other developers or even of

7
00:00:26,520 --> 00:00:32,970
‫other namespaces directly without having to write a lot of code manually again and again and again,

8
00:00:32,970 --> 00:00:34,430
‫which was there before.

9
00:00:34,440 --> 00:00:38,640
‫And this really reduces repeated or redundant code.

10
00:00:39,120 --> 00:00:46,860
‫So the idea of inheritance is basically it's a fundamental concept of object oriented programming.

11
00:00:46,890 --> 00:00:54,540
‫It allows you to define a child class that reuses or inherits, extends, or modifies a parent class's

12
00:00:54,540 --> 00:00:55,320
‫behavior.

13
00:00:55,860 --> 00:00:59,870
‫The class whose members are inherited is called the base class.

14
00:00:59,880 --> 00:01:04,770
‫The class that inherits the members of the base class is called the derived class.

15
00:01:05,380 --> 00:01:06,990
‫Okay, so what does this mean?

16
00:01:07,050 --> 00:01:11,790
‫Well, in simple terms, if you have more than one class with the same code or functionality, but it

17
00:01:11,790 --> 00:01:16,980
‫differs slightly, we can actually put this repeated or redundant code in a separate class and then

18
00:01:16,980 --> 00:01:20,160
‫make our class this inherit from it.

19
00:01:20,280 --> 00:01:26,940
‫This code can be method's functionality, so to speak, or properties which are the attributes of our

20
00:01:26,940 --> 00:01:27,690
‫classes.

21
00:01:27,840 --> 00:01:29,700
‫So let's look at an example.

22
00:01:29,700 --> 00:01:33,810
‫And therefore I created a new project here, which I call Inheritance Demo.

23
00:01:34,380 --> 00:01:36,840
‫All right, so let's go ahead and look at this example.

24
00:01:36,840 --> 00:01:41,940
‫So usually when you are working with multiple classes, you go ahead and create a new class here.

25
00:01:42,150 --> 00:01:43,890
‫So let's do that here as well.

26
00:01:43,920 --> 00:01:48,840
‫You could, of course, create the class in the same file, but that's not good practice.

27
00:01:48,840 --> 00:01:51,930
‫So let's go ahead and call this class radio.

28
00:01:51,960 --> 00:01:52,290
‫All right.

29
00:01:52,290 --> 00:01:55,530
‫So here's the class, say radio ad.

30
00:01:55,530 --> 00:01:59,460
‫And now we have this radial class, which is in the same namespace.

31
00:01:59,730 --> 00:02:05,070
‫So both classes, the program C is where we have our main method, which is the starting point of our

32
00:02:05,070 --> 00:02:08,520
‫application and the radial class are in the same file.

33
00:02:08,550 --> 00:02:10,560
‫So we're going to have two classes.

34
00:02:10,560 --> 00:02:13,560
‫One will be radio and the other one will be TV.

35
00:02:13,650 --> 00:02:15,690
‫Let's just assume we have a couple of properties.

36
00:02:15,690 --> 00:02:21,810
‫So for example, a boolean that determines the state of the radio is it turned on, and then the brand

37
00:02:21,810 --> 00:02:22,590
‫of the radio.

38
00:02:22,590 --> 00:02:26,400
‫So is it Panasonic or whatever other brands there are?

39
00:02:26,670 --> 00:02:33,900
‫And then we have a simple constructor here, so you should definitely have an understanding of the core

40
00:02:33,900 --> 00:02:35,130
‫concepts of classes.

41
00:02:35,130 --> 00:02:40,050
‫If you want to fully understand inheritance, that's generally something that I would recommend understanding

42
00:02:40,050 --> 00:02:43,380
‫before getting to inheritance because it's building on top of each other.

43
00:02:43,850 --> 00:02:44,130
‫Okay.

44
00:02:44,160 --> 00:02:49,620
‫So then I want to have two methods because this is basically going to be the functionality.

45
00:02:49,620 --> 00:02:56,160
‫So one is going to switch the radio on, it will be the switch on method and the other one will be the

46
00:02:56,160 --> 00:02:57,090
‫switch off method.

47
00:02:57,090 --> 00:03:02,400
‫So you can turn the radio on and off or switch it on off using these two methods.

48
00:03:02,550 --> 00:03:08,610
‫And then we will have another method which will allow us to listen to the radio.

49
00:03:09,090 --> 00:03:14,070
‫So we have this method here called Listen Radio and it will check.

50
00:03:14,100 --> 00:03:16,200
‫Is the radio turned on right now?

51
00:03:16,200 --> 00:03:21,540
‫So is this is on property here, this boolean, is it going to be in fact true?

52
00:03:21,540 --> 00:03:27,180
‫And if that's true, then we can listen to the radio and the way we are going to indicate that we are

53
00:03:27,180 --> 00:03:32,660
‫listening to the radio will just be with this console red line statement saying listening to the radio

54
00:03:32,670 --> 00:03:39,000
‫and otherwise we're going to print this error message saying radio is switched off, switch it on first.

55
00:03:39,030 --> 00:03:39,240
‫Okay.

56
00:03:39,240 --> 00:03:43,230
‫So before we can listen to it, we need to turn it on.

57
00:03:43,320 --> 00:03:43,710
‫All right.

58
00:03:43,710 --> 00:03:45,480
‫So that's our radio now.

59
00:03:45,510 --> 00:03:49,530
‫Now, imagine you have another class, which is going to be.

60
00:03:50,450 --> 00:03:51,740
‫The TV.

61
00:03:52,070 --> 00:03:54,050
‫So let's go ahead and create a new class.

62
00:03:54,050 --> 00:04:00,380
‫And therefore you can go over here to add and then add class and give this class a name.

63
00:04:00,380 --> 00:04:02,000
‫I'm going to call it TV.

64
00:04:02,120 --> 00:04:09,440
‫And now in this class, I will go ahead and have a couple of properties similarly to what we had here.

65
00:04:09,440 --> 00:04:15,410
‫So basically, I'm going to also have the state if it's turned on or off.

66
00:04:15,440 --> 00:04:17,840
‫So let's add those two properties in here.

67
00:04:17,870 --> 00:04:23,660
‫Then I will have a simple constructor which allows me to set those values when I'm creating a new object

68
00:04:23,660 --> 00:04:24,650
‫of TV.

69
00:04:24,650 --> 00:04:29,960
‫So here pull is on as well as string brand, which sets the properties.

70
00:04:30,770 --> 00:04:40,220
‫Then I will have the individual other methods so I can turn on the TV and turn it off similar to what

71
00:04:40,220 --> 00:04:43,790
‫I did in the radio so I can basically copy this code.

72
00:04:43,790 --> 00:04:48,920
‫But it will be slightly different because we had the comments which said radio here, but now this will

73
00:04:48,920 --> 00:04:49,610
‫be TV.

74
00:04:49,610 --> 00:04:55,190
‫So this method will turn on the TV and this one will turn it off or switch it off.

75
00:04:56,030 --> 00:05:05,180
‫So then we just need to have another method which will allow us to watch the TV and it will do something

76
00:05:05,180 --> 00:05:07,520
‫very similar to what our radio does.

77
00:05:07,550 --> 00:05:12,560
‫It allows us to watch the TV only if the TV is on.

78
00:05:12,590 --> 00:05:15,800
‫If it's off, we will need to turn on the TV first.

79
00:05:16,280 --> 00:05:21,170
‫Okay, so now we have these two classes and if you look at them, they are awfully similar.

80
00:05:21,200 --> 00:05:27,920
‫So there is a lot of stuff that is exactly the same, basically because this property is on as well

81
00:05:27,920 --> 00:05:29,720
‫as this brand, they are the same.

82
00:05:29,720 --> 00:05:33,080
‫We have them in both classes, so basically we have redundant code.

83
00:05:33,080 --> 00:05:37,850
‫We had to copy and paste a bunch of code and it's more or less the same.

84
00:05:38,210 --> 00:05:46,820
‫So how can we make it so that we don't have to copy and paste a lot of code and rewrite code and basically

85
00:05:46,820 --> 00:05:47,810
‫have redundant code?

86
00:05:47,810 --> 00:05:52,130
‫Well, that's the whole point of the concept of inheritance.

87
00:05:52,130 --> 00:05:54,710
‫So inheritance comes to the rescue.

88
00:05:54,740 --> 00:05:59,810
‫We can solve this issue by creating a third class called electrical device.

89
00:05:59,810 --> 00:06:05,210
‫This will contain all of the shared functionalities and properties of an electrical device we have.

90
00:06:05,210 --> 00:06:07,550
‫So let's look at those.

91
00:06:07,550 --> 00:06:10,520
‫What are the ones that we have that are the same?

92
00:06:10,520 --> 00:06:15,200
‫So what are the properties that are the same for our TV as well as the radio?

93
00:06:15,410 --> 00:06:21,020
‫Well, it's in our case all of the properties, actually, but it doesn't have to be all of them.

94
00:06:21,020 --> 00:06:23,690
‫In this case it will be because we don't have more properties.

95
00:06:23,690 --> 00:06:26,840
‫But the two properties that we have that will be the same.

96
00:06:26,840 --> 00:06:33,860
‫So is on and brand are both properties that exist in TV as well as in radio.

97
00:06:34,040 --> 00:06:40,280
‫So our new class should have those two properties and then we have the two methods which allow us to

98
00:06:40,310 --> 00:06:46,760
‫switch the TV on, the radio on or the radio off and the TV off as well.

99
00:06:47,840 --> 00:06:54,920
‫So for you, a little exercise if you want to try this, because I assume that you are not a pro and

100
00:06:54,920 --> 00:06:58,790
‫programming at that point, but you will feel a lot more confident when you try this.

101
00:06:58,790 --> 00:07:06,980
‫So go ahead and create a class that has all of these properties and these methods that we can or that

102
00:07:06,980 --> 00:07:12,080
‫are shared between the two classes, create them in a separate class and call this class electrical

103
00:07:12,080 --> 00:07:12,950
‫device.

104
00:07:12,950 --> 00:07:17,360
‫Actually, you can call it however you want, but I'm going to call it electrical device like such.

105
00:07:18,510 --> 00:07:18,960
‫Okay.

106
00:07:18,990 --> 00:07:21,000
‫So I hope you passed the video and tried it.

107
00:07:21,000 --> 00:07:25,620
‫So I'm going to create a new class and put a way, of course, you see, you can use the shortcut control

108
00:07:25,620 --> 00:07:27,390
‫case, so let's do that.

109
00:07:27,390 --> 00:07:35,850
‫In this case, Control K C and this will open up this window here and let me change it to electrical.

110
00:07:36,990 --> 00:07:39,000
‫Device like so.

111
00:07:39,330 --> 00:07:44,280
‫And now this class will have the properties that we are sharing between the two other classes.

112
00:07:44,280 --> 00:07:45,720
‫So let me put them in here.

113
00:07:45,750 --> 00:07:49,650
‫The boolean that determines the state of the electrical device, is it turned on or not?

114
00:07:49,920 --> 00:07:51,720
‫And then the brand of the device.

115
00:07:52,020 --> 00:07:56,310
‫And then of course, we need to have a constructor.

116
00:07:56,430 --> 00:07:58,680
‫So electrical device is on.

117
00:07:58,680 --> 00:08:02,910
‫And Brent and finally we have the functionality which are methods.

118
00:08:02,910 --> 00:08:08,190
‫So whenever you have functionality, you put them into methods and the functionality is to turn something

119
00:08:08,190 --> 00:08:09,750
‫on or turn something off.

120
00:08:09,750 --> 00:08:14,970
‫So whenever there is an action happening with your class or with the object that you are using, you

121
00:08:14,970 --> 00:08:16,680
‫will need to use methods.

122
00:08:16,890 --> 00:08:18,090
‫And that's what we're doing here.

123
00:08:18,090 --> 00:08:24,870
‫So we're using a method to turn something on, in this case the electrical device, and to turn it off

124
00:08:24,870 --> 00:08:26,790
‫or switch it on and switch it off.

125
00:08:26,790 --> 00:08:26,970
‫Okay.

126
00:08:27,060 --> 00:08:29,790
‫So that's basically what we're doing here.

127
00:08:29,790 --> 00:08:35,160
‫So now that we have our shared properties and methods in one class, let's make the other class of the

128
00:08:35,160 --> 00:08:42,330
‫TV and radio classes inherit from this class or in other words, extend this class.

129
00:08:42,570 --> 00:08:45,270
‫So this is just a different term that you can use here.

130
00:08:45,390 --> 00:08:51,120
‫So our TV and our radio will now extend the electrical devices class.

131
00:08:51,330 --> 00:08:52,950
‫So how can we do that?

132
00:08:52,950 --> 00:08:55,890
‫Well, let's start with the radio, because the TV will be done.

133
00:08:55,890 --> 00:08:57,090
‫A little challenge for you.

134
00:08:57,090 --> 00:08:57,270
‫What?

135
00:08:57,270 --> 00:08:59,400
‫You will have to do it yourself.

136
00:08:59,400 --> 00:09:08,100
‫So here you use the colon and then the name of the class that you want to inherit from electrical device

137
00:09:08,100 --> 00:09:16,050
‫is the class that our radio now will inherit from, or our radio will extend the functionality of the

138
00:09:16,050 --> 00:09:17,910
‫electrical device class.

139
00:09:18,850 --> 00:09:19,330
‫Okay.

140
00:09:19,330 --> 00:09:22,660
‫So Colon and then the name of the class that you want to extend.

141
00:09:22,660 --> 00:09:29,620
‫And what's important is, is of course, that this class has to be either in the same namespace or you

142
00:09:29,620 --> 00:09:32,200
‫have to add the namespace up here.

143
00:09:32,200 --> 00:09:37,240
‫So in our case, we're not using any of those, we're just using system, but as we are in the same

144
00:09:37,240 --> 00:09:42,610
‫namespace, so the electrical device says class is in the same namespace as radio and TV.

145
00:09:42,610 --> 00:09:47,920
‫We can just do it like so, but now we can see that our boolean has a warning here.

146
00:09:47,920 --> 00:09:55,510
‫So when you hover over your ID, so Visual Studio is going to tell you Radio DOT is on hides, inherited

147
00:09:55,510 --> 00:10:00,400
‫member electrical devices is on use the new keyword if hiding was intended.

148
00:10:00,760 --> 00:10:10,090
‫So basically we are using the same property name and here you want to avoid that because you have this

149
00:10:10,090 --> 00:10:14,770
‫property, so to speak, already because you're inheriting it from the electrical device.

150
00:10:14,980 --> 00:10:22,030
‫So now you can just hide it or override it with this one that you have created here if you want to use

151
00:10:22,030 --> 00:10:27,190
‫something with the exact same name, but it should behave somehow differently, then you can do that.

152
00:10:27,190 --> 00:10:31,150
‫Even though that's not good practice necessarily depends on the use case, of course.

153
00:10:31,150 --> 00:10:39,340
‫So this is because now the radio class contains two properties of the same name we are hiding or covering.

154
00:10:39,340 --> 00:10:40,600
‫That's a different term here.

155
00:10:40,600 --> 00:10:44,860
‫The properties that we inherited from the electrical device class.

156
00:10:44,860 --> 00:10:48,730
‫So we will remove the redundant code that we don't need anymore.

157
00:10:48,730 --> 00:10:49,960
‫So let's get rid of that.

158
00:10:50,200 --> 00:10:54,970
‫And of course the redundant code is not just assigning or creating the properties but also having these

159
00:10:54,970 --> 00:10:55,690
‫methods here.

160
00:10:55,690 --> 00:10:57,520
‫So let's get rid of those as well.

161
00:10:57,910 --> 00:11:04,810
‫Now we have another error that appears here and that is this radio constructor that seems to have an

162
00:11:04,810 --> 00:11:05,410
‫issue.

163
00:11:05,440 --> 00:11:12,220
‫It says there is no argument given that corresponds to the required formal parameter is on of electrical

164
00:11:12,220 --> 00:11:14,770
‫device, electrical device, pool string.

165
00:11:14,980 --> 00:11:17,590
‫So what is this electrical device or electrical device?

166
00:11:17,590 --> 00:11:20,770
‫Pool string Well, it's this one here.

167
00:11:20,770 --> 00:11:22,240
‫It's this constructor.

168
00:11:22,240 --> 00:11:28,870
‫Since our properties are coming from the base class and our base class contains a constructor, we can

169
00:11:28,870 --> 00:11:32,380
‫use the base keyword to pass our base class.

170
00:11:32,410 --> 00:11:39,100
‫It's constructor arguments because these are the only two properties we have and our constructor in

171
00:11:39,100 --> 00:11:41,530
‫the child class will have an empty body.

172
00:11:41,860 --> 00:11:44,290
‫So that is a lot of talk.

173
00:11:44,290 --> 00:11:49,450
‫But basically what this means is because our radio constructor isn't any more complex than the base

174
00:11:49,450 --> 00:11:57,160
‫one, we can just go ahead and say base and here is on and brand.

175
00:11:58,300 --> 00:11:59,080
‫Like so.

176
00:11:59,110 --> 00:12:02,260
‫And then we don't need a body for our radio.

177
00:12:02,530 --> 00:12:08,410
‫So this constructor will basically say please pass the is on as well as the brand properties that are

178
00:12:08,410 --> 00:12:16,300
‫passed to the radio object that when it's created pass it over to the electrical device constructor

179
00:12:16,300 --> 00:12:23,560
‫because basically our radio is inheriting from electrical device and therefore we can do that so we

180
00:12:23,560 --> 00:12:26,080
‫can just pass it over to electrical device.

181
00:12:26,080 --> 00:12:32,440
‫And what that will do is it will basically set the properties is on as well as brand based on the values

182
00:12:32,440 --> 00:12:33,340
‫that are passed.

183
00:12:34,090 --> 00:12:34,870
‫So this is.

184
00:12:35,610 --> 00:12:37,170
‫The more complicated part.

185
00:12:37,170 --> 00:12:43,560
‫But the power here is really that we don't have to build redundant code and well, the work is done

186
00:12:43,560 --> 00:12:44,130
‫for us.

187
00:12:44,130 --> 00:12:48,330
‫So it really saves us a lot of time and writing code as well.

188
00:12:51,100 --> 00:12:57,280
‫In a later example, we will see how to use the constructors body in the child class to initialize its

189
00:12:57,280 --> 00:12:58,720
‫own unique properties.

190
00:12:59,050 --> 00:13:02,620
‫To just quickly reemphasize the radio class here.

191
00:13:03,550 --> 00:13:05,560
‫Is our child class.

192
00:13:07,100 --> 00:13:13,880
‫So the inheriting class and the electrical device is our parent class.

193
00:13:14,240 --> 00:13:16,280
‫So the base class.

194
00:13:16,910 --> 00:13:19,520
‫So we are going to inherit.

195
00:13:19,520 --> 00:13:23,120
‫So our radio inherits from electrical device.

196
00:13:23,600 --> 00:13:25,910
‫So the child inherits from the parent.

197
00:13:25,940 --> 00:13:31,430
‫Basically, your parents have a certain DNA and you have the same DNA, but you have a little more to

198
00:13:31,430 --> 00:13:32,090
‫it, so to speak.

199
00:13:32,090 --> 00:13:34,130
‫So that's how you could think about it.

200
00:13:34,910 --> 00:13:35,540
‫All right.

201
00:13:35,540 --> 00:13:37,330
‫So now a little challenge for you.

202
00:13:37,370 --> 00:13:41,090
‫Adjust the TV class so that it inherits from electrical device as well.

203
00:13:41,270 --> 00:13:43,070
‫So pause the video and try that, please.

204
00:13:44,120 --> 00:13:44,780
‫All right.

205
00:13:44,780 --> 00:13:45,980
‫I hope you tried it.

206
00:13:45,980 --> 00:13:49,640
‫So first we need to add colon electrical device.

207
00:13:50,060 --> 00:13:52,250
‫Then we can get rid of the redundant code.

208
00:13:52,250 --> 00:13:59,450
‫So the repetitive code, because we have it in our base class already, and this means that we can use

209
00:13:59,450 --> 00:14:01,760
‫it in our TV class directory as well.

210
00:14:01,910 --> 00:14:12,020
‫And now we can also adjust this here, saying that we're going to pass the data on to our base class.

211
00:14:12,110 --> 00:14:14,720
‫And of course, we don't need to set that here as well.

212
00:14:14,720 --> 00:14:20,720
‫But as I said in the later example, we are going to see how we can still use the body efficiently and

213
00:14:20,720 --> 00:14:22,730
‫that is going to be basically it.

214
00:14:23,000 --> 00:14:28,820
‫Now we can just go ahead to our program CSV file and actually check our code here.

215
00:14:28,970 --> 00:14:34,490
‫And by checking our code, I mean create objects of our radio and test it.

216
00:14:34,490 --> 00:14:37,250
‫So let's go ahead, create in radio object.

217
00:14:37,550 --> 00:14:42,110
‫I'm going to call this one my radio and this will be a new radio object.

218
00:14:42,230 --> 00:14:44,300
‫Now, of course, I need to pass whether it's on.

219
00:14:44,300 --> 00:14:50,720
‫So I'm going to turn it off at the beginning and I'm going to say it's going to be made by Sony, so

220
00:14:50,720 --> 00:14:52,070
‫the brand will be Sony.

221
00:14:52,820 --> 00:14:55,550
‫Now I can access the properties.

222
00:14:55,550 --> 00:15:02,840
‫You can see here this tool item, the properties of my radio, which is the brand and the is own property

223
00:15:03,410 --> 00:15:06,110
‫and I can also access IT methods.

224
00:15:06,110 --> 00:15:09,380
‫So switch on, switch off, listen radio.

225
00:15:09,380 --> 00:15:15,590
‫And then you can also see that there are some methods that we never created ourselves which are just

226
00:15:15,590 --> 00:15:22,880
‫there from the get go, because every class inherits from the object class and the object class has

227
00:15:22,880 --> 00:15:28,970
‫a two string method as well as a get type get hashCode and equals method.

228
00:15:29,420 --> 00:15:35,930
‫So these methods, they are there for every single class that you are creating in C sharp because basically

229
00:15:36,170 --> 00:15:42,770
‫we don't see it, but internally it inherits from the object class like so.

230
00:15:42,770 --> 00:15:48,380
‫So every class inherits from the object class and that's why we have these different methods.

231
00:15:48,560 --> 00:15:51,260
‫But now let's first of all switch it on.

232
00:15:51,770 --> 00:15:53,150
‫So here, switch on.

233
00:15:54,410 --> 00:15:59,210
‫This will switch on our radio and now we can listen to our radio.

234
00:15:59,210 --> 00:16:00,500
‫So hear my radio.

235
00:16:00,530 --> 00:16:01,610
‫Dot, listen.

236
00:16:01,610 --> 00:16:02,270
‫Radio.

237
00:16:03,920 --> 00:16:08,240
‫Now let's run this and this will allow us to listen to our radio.

238
00:16:09,880 --> 00:16:12,220
‫So that we are listening to the radio.

239
00:16:12,550 --> 00:16:14,930
‫So we switch to radio on.

240
00:16:14,950 --> 00:16:18,880
‫Let's now not switch the radio on and listen to radio.

241
00:16:18,880 --> 00:16:20,920
‫And it will say radio switched off.

242
00:16:20,920 --> 00:16:22,450
‫Switch it on first.

243
00:16:23,930 --> 00:16:28,490
‫All right, so now let's do the same thing with our TV.

244
00:16:28,820 --> 00:16:31,260
‫Let's go ahead and create a TV object.

245
00:16:31,280 --> 00:16:38,810
‫I'm going to call this on my TV, which will be a new TV object, and this one will be turned off as

246
00:16:38,810 --> 00:16:39,350
‫well.

247
00:16:39,350 --> 00:16:41,000
‫And it will be a Samsung device.

248
00:16:42,630 --> 00:16:50,610
‫And now let's go ahead and use my TV dot switch on to switch it on.

249
00:16:52,620 --> 00:16:55,770
‫And then let's call the watch TV method.

250
00:16:57,100 --> 00:16:57,370
‫Mike.

251
00:16:57,370 --> 00:17:04,210
‫So now let's run this and we will see that now our TV is turned on and we're watching it while listening

252
00:17:04,210 --> 00:17:05,170
‫to the radio.

253
00:17:05,200 --> 00:17:06,970
‫So quite a task there.

254
00:17:06,970 --> 00:17:10,120
‫But basically our code does what we want it to.

255
00:17:11,760 --> 00:17:16,620
‫So now you see we call the switch on method for the radio as well as the TV.

256
00:17:16,650 --> 00:17:23,640
‫Even though if we look at the TV class, it doesn't have this method, so it doesn't have a switch on

257
00:17:23,670 --> 00:17:26,490
‫to well, switch on or switch off method.

258
00:17:26,580 --> 00:17:31,950
‫The radio doesn't have those methods either, but that is because they are inheriting from the electrical

259
00:17:31,950 --> 00:17:37,530
‫device which has those methods switch on and switch off that we can use it.

260
00:17:37,980 --> 00:17:41,370
‫So basically here we're using the method of the.

261
00:17:42,220 --> 00:17:43,000
‫Base class.

262
00:17:43,000 --> 00:17:43,790
‫So here.

263
00:17:43,810 --> 00:17:45,820
‫Method of base class.

264
00:17:46,720 --> 00:17:51,610
‫And here we're using the method of child class.

265
00:17:52,800 --> 00:17:57,750
‫So this switch on method comes from the parent class and the watch TV method is from the child class.

266
00:17:57,750 --> 00:18:03,990
‫So now we can create the code that is unique to the class, and it's not repetitive, so to speak,

267
00:18:03,990 --> 00:18:06,870
‫directly in the TV class as well as in the radio class.

268
00:18:06,870 --> 00:18:12,960
‫But everything that is the same and will be relevant for electrical devices in general is something

269
00:18:12,960 --> 00:18:14,580
‫that we can create in here.

270
00:18:15,240 --> 00:18:19,920
‫There is a lot more to inheritance and of course we're going to look into all of that throughout this

271
00:18:19,920 --> 00:18:20,460
‫chapter.

272
00:18:20,460 --> 00:18:21,990
‫So see you in the next video.