1 00:00:00,630 --> 00:00:09,420 And as you can see here inside this main class here we are actually creating an object from these chat 2 00:00:09,420 --> 00:00:11,530 class called Cat 1. 3 00:00:11,850 --> 00:00:18,000 And here we are actually passing some values to the constructor of this cat class. 4 00:00:18,060 --> 00:00:24,180 As you can see whenever we create an object from this track class the constructor of this cat class 5 00:00:24,180 --> 00:00:25,100 is going to be called. 6 00:00:25,110 --> 00:00:25,710 OK. 7 00:00:25,800 --> 00:00:30,130 So as you can see here you are actually passing the name of this chat. 8 00:00:30,450 --> 00:00:33,610 And here we are actually passing the color of this card. 9 00:00:33,720 --> 00:00:40,200 The amount of speed of this card the amount of power of this card and this value is for the number of 10 00:00:40,200 --> 00:00:48,060 legs of this cat and this value is for the can hunt other animals instance variable A-okay which we 11 00:00:48,060 --> 00:00:50,010 actually passed the true value. 12 00:00:50,340 --> 00:00:58,920 And here in line 52 we are actually trying to output these values to the screen by calling this to a 13 00:00:58,930 --> 00:01:04,460 string Mefford which we actually overnighted inside this cat class as you can see here. 14 00:01:04,560 --> 00:01:12,090 We actually overgraded this to a string Meffert in order to create a human readable description of DS 15 00:01:12,320 --> 00:01:16,930 for instance variables and then outputs of those values to the screen here. 16 00:01:17,010 --> 00:01:19,560 As you can see here chat's 1:59 a string. 17 00:01:19,740 --> 00:01:23,790 So now let's actually run our project and see what happens. 18 00:01:23,790 --> 00:01:28,110 So as you can see here now these values are outputted to the screen. 19 00:01:28,140 --> 00:01:28,650 OK. 20 00:01:28,860 --> 00:01:33,780 The name of our cat is my cat the color of our cat is white. 21 00:01:33,780 --> 00:01:35,900 The speed of our cat is 40. 22 00:01:35,940 --> 00:01:38,290 The power of our cat is 50. 23 00:01:38,340 --> 00:01:40,950 Number of legs of our cat is four. 24 00:01:41,490 --> 00:01:43,590 And our cat can fight. 25 00:01:43,590 --> 00:01:44,900 OK a fight. 26 00:01:44,910 --> 00:01:45,410 True. 27 00:01:45,500 --> 00:01:46,120 OK. 28 00:01:46,260 --> 00:01:48,630 This means that our cat can fight. 29 00:01:48,660 --> 00:01:49,150 OK. 30 00:01:49,260 --> 00:01:55,240 So as you can see here now you can understand the power of inheritance in Java as you can see here inside 31 00:01:55,310 --> 00:01:56,300 it cat class. 32 00:01:56,310 --> 00:02:01,720 We deleted all of those duplicated codes that were inside this Chad class. 33 00:02:01,770 --> 00:02:02,370 OK. 34 00:02:02,580 --> 00:02:09,760 We just actually inheriting all of those features and behaviors that are inside this Animal class. 35 00:02:09,780 --> 00:02:10,150 OK. 36 00:02:10,170 --> 00:02:17,970 So we didn't need to actually redeclare the variables and the methods that were created inside this 37 00:02:18,270 --> 00:02:24,360 Animal class inside this Animal class we actually created this instance variables for example the name 38 00:02:24,360 --> 00:02:31,020 of our animal the color of our animal the amount of speed of our animal and the amount of power of our 39 00:02:31,020 --> 00:02:31,670 animal. 40 00:02:31,860 --> 00:02:37,920 And as you can see we created a constructor here and we actually initialized these instance variables 41 00:02:37,920 --> 00:02:45,690 here and we also created some getters and setters for these instance rally abettors and we we even created 42 00:02:45,960 --> 00:02:47,760 a shoestring team effort here. 43 00:02:48,150 --> 00:02:48,690 OK. 44 00:02:48,840 --> 00:02:55,200 At inciters twittering Meffert as you can see here we actually put our own codes in order to output 45 00:02:55,260 --> 00:02:56,850 these values to the screen. 46 00:02:57,030 --> 00:03:01,550 So inside this math class we actually put some duplicated codes here. 47 00:03:01,580 --> 00:03:05,740 We didn't need to actually implement some of these codes here. 48 00:03:05,970 --> 00:03:14,430 So now I want to show you how we can actually again use the power of inheritance in order to actually 49 00:03:14,730 --> 00:03:19,960 write less courts OK and write more maintainable codes. 50 00:03:19,980 --> 00:03:20,560 OK. 51 00:03:20,790 --> 00:03:28,200 So now I want to show you how you can actually delete those duplicated codes and write less codes and 52 00:03:28,320 --> 00:03:30,960 write more maintainable codes. 53 00:03:31,440 --> 00:03:32,380 OK everyone. 54 00:03:32,400 --> 00:03:38,700 Now let's actually delete these lines of code here because I want to show you how you can actually use 55 00:03:38,880 --> 00:03:41,640 the power of inheritance in your codes. 56 00:03:41,670 --> 00:03:47,670 So as you can see here inside this animal class we have this line of code here that is completely useful 57 00:03:47,880 --> 00:03:48,860 for our cat class. 58 00:03:48,870 --> 00:03:49,450 OK. 59 00:03:49,640 --> 00:03:55,650 This method actually outputs are the name of an object the color of an object the amount of speed of 60 00:03:55,650 --> 00:04:00,090 our object and also it outputs the amount of power of our object. 61 00:04:00,090 --> 00:04:00,990 OK. 62 00:04:01,200 --> 00:04:10,560 So here inside this math class in order to use the implementations that are in sight these are two string 63 00:04:10,570 --> 00:04:15,010 Mefford that is overrated inside these animal class. 64 00:04:15,270 --> 00:04:22,610 Inside this cat class inside these two string Meffert I can just type in return super. 65 00:04:22,630 --> 00:04:26,290 So remember this super refers to the superclass. 66 00:04:26,290 --> 00:04:30,770 So what is the superclass the superclass of this chat class is Animal class. 67 00:04:30,790 --> 00:04:31,540 OK. 68 00:04:31,990 --> 00:04:42,180 Return super dot to a string so as you can see here now we did manage to successfully refer to the codes 69 00:04:42,690 --> 00:04:47,520 that are inside these is Meffert inside this animal class. 70 00:04:47,550 --> 00:04:48,430 OK. 71 00:04:48,810 --> 00:04:54,220 So superior first to this animal class that was three in the first two this method and then it's going 72 00:04:54,220 --> 00:04:58,370 to actually execute these lines of code here inside these two a string Meffert. 73 00:04:58,380 --> 00:04:59,440 OK. 74 00:04:59,460 --> 00:05:04,160 So inside this cathe class we actually typed in here return super's that was Thring. 75 00:05:04,200 --> 00:05:04,690 OK. 76 00:05:04,830 --> 00:05:08,000 So let's actually run our project and see what happens. 77 00:05:08,130 --> 00:05:12,520 So as you can see here these are the values that are outputted to the screen. 78 00:05:12,540 --> 00:05:18,520 OK name my cats color white speed 40 powerful 80. 79 00:05:18,720 --> 00:05:25,500 So inside this main activity that java file here as you can see are actually specified some values for 80 00:05:25,500 --> 00:05:26,820 this cat object. 81 00:05:26,820 --> 00:05:34,650 And here as you can see in this emulator as you can see the name of my child is my cats the color of 82 00:05:34,650 --> 00:05:39,450 my cat is white and this is the value for my speed. 83 00:05:39,780 --> 00:05:42,440 And this is the value for the power of my cat. 84 00:05:42,720 --> 00:05:50,030 And we also actually specified two other values for my cat object which we can't actually see in the 85 00:05:50,080 --> 00:05:54,570 emulator how we can actually output these values to the screen. 86 00:05:54,570 --> 00:05:56,940 So and so it is Chatz class as you can see here. 87 00:05:56,970 --> 00:06:04,680 We did manage to actually use implementations that are inside the twisting Meffert inside this Animal 88 00:06:04,680 --> 00:06:06,810 class in our chat class. 89 00:06:06,810 --> 00:06:07,420 OK. 90 00:06:07,590 --> 00:06:10,020 By just typing super THAT WAS think OK. 91 00:06:10,030 --> 00:06:15,220 Superiorly first the superclass which is the Animal class that was three in the first two that westering 92 00:06:15,240 --> 00:06:17,780 Meffert that is inside the Animal class. 93 00:06:17,820 --> 00:06:18,270 OK. 94 00:06:18,330 --> 00:06:20,460 And here we actually used it. 95 00:06:20,460 --> 00:06:26,450 These are capabilities that are inside this Animal class but inside is Kathe class. 96 00:06:26,460 --> 00:06:32,300 We've got two other instance variables that are specific only to this class Class. 97 00:06:32,400 --> 00:06:33,300 OK. 98 00:06:33,690 --> 00:06:40,470 So in order to actually output these values to the screen here I can just put in a plus operator here. 99 00:06:41,410 --> 00:06:45,610 And then I can just type in strange dot format. 100 00:06:46,330 --> 00:06:55,090 And here first of all I can actually specify the formatting instructions here present as Colan percent 101 00:06:55,120 --> 00:07:00,550 the space per cent as Colan per cent B. 102 00:07:00,610 --> 00:07:03,970 And then I can actually specify the arguments. 103 00:07:03,970 --> 00:07:10,840 So for the first Torchin I need to actually specify I need to actually putting out an argument of types 104 00:07:10,850 --> 00:07:11,290 3. 105 00:07:11,320 --> 00:07:15,730 So I just put in a string literal here inside these double quotes. 106 00:07:15,730 --> 00:07:20,190 I can just type in number of legs. 107 00:07:20,470 --> 00:07:21,140 OK. 108 00:07:21,550 --> 00:07:27,180 And for this person D I need to actually specify an argument of type integer. 109 00:07:27,450 --> 00:07:28,100 OK. 110 00:07:28,150 --> 00:07:30,650 Number of legs. 111 00:07:30,880 --> 00:07:36,280 And then again I need to actually specify an argument of type string here. 112 00:07:36,310 --> 00:07:42,860 So as you can see here this percent as talken needs an argument of type string. 113 00:07:43,030 --> 00:07:45,000 So I just put in two double quotes here. 114 00:07:45,220 --> 00:07:55,770 So here I want to actually use a string literal again fight colon and then I refer to the name of my 115 00:07:55,770 --> 00:08:00,710 instance variable as you can see can hunt other animals. 116 00:08:00,720 --> 00:08:01,330 OK. 117 00:08:01,440 --> 00:08:07,840 So as you can see here we've got this person's behere and this token is for values of type Boolean. 118 00:08:07,860 --> 00:08:13,390 OK Chad hunt other animals so let's actually run our project and see what happens. 119 00:08:13,560 --> 00:08:21,330 So as you can see here now these values are out here a number of legs for fight true so we can actually 120 00:08:21,330 --> 00:08:23,310 put a space between these two values. 121 00:08:23,310 --> 00:08:27,680 Number 30 and this number of legs a string literal here. 122 00:08:27,690 --> 00:08:34,310 So inside this animal class here I can actually put a space after this person D here and if I don't 123 00:08:34,350 --> 00:08:35,380 my project again. 124 00:08:35,670 --> 00:08:39,210 Now we can't see a space between these two values. 125 00:08:39,210 --> 00:08:40,020 OK. 126 00:08:40,170 --> 00:08:42,510 Number fretty our space. 127 00:08:42,510 --> 00:08:43,230 Number of legs. 128 00:08:43,230 --> 00:08:44,240 OK. 129 00:08:44,970 --> 00:08:45,290 OK. 130 00:08:45,300 --> 00:08:46,660 So what's going on here. 131 00:08:46,700 --> 00:08:52,070 What did they do to actually come out with these values to the screen in this math class. 132 00:08:52,110 --> 00:09:01,050 As you can see first of all I actually used the implementations that are inside the superclass of these 133 00:09:01,420 --> 00:09:01,960 chat class. 134 00:09:01,960 --> 00:09:04,190 OK so the superclass of this class class is animal. 135 00:09:04,230 --> 00:09:04,820 OK. 136 00:09:05,070 --> 00:09:11,010 I actually use the implementations that are inside the three inch Meffert that is inside these Animal 137 00:09:11,010 --> 00:09:11,320 class. 138 00:09:11,330 --> 00:09:12,010 OK. 139 00:09:12,240 --> 00:09:14,640 The superclass of this class is Animal class. 140 00:09:14,700 --> 00:09:15,330 OK. 141 00:09:15,330 --> 00:09:20,200 So here we actually use the implementations of that Smurfette inside the superclass. 142 00:09:20,490 --> 00:09:29,580 And here we actually use this D-plus operator in order to concatenate these two string values here. 143 00:09:29,580 --> 00:09:30,250 OK. 144 00:09:30,360 --> 00:09:35,630 So this piece of code here actually returns a value of type strange. 145 00:09:35,760 --> 00:09:41,510 OK so we can actually say that this piece of code is our streambed value. 146 00:09:41,660 --> 00:09:42,360 OK. 147 00:09:42,810 --> 00:09:50,790 And here we actually put a plus operator here in order to concatenate this value with another string 148 00:09:50,820 --> 00:09:51,190 value. 149 00:09:51,210 --> 00:09:51,630 OK. 150 00:09:51,720 --> 00:09:57,470 So again this string value here provides us with another string value. 151 00:09:57,500 --> 00:10:04,590 Ok 3 in that format as you can see here first we actually specified the formatting instructions of this 152 00:10:05,010 --> 00:10:10,880 method and then we actually put some arguments that are related to these tokens. 153 00:10:10,890 --> 00:10:11,470 OK. 154 00:10:11,670 --> 00:10:14,260 Number of legs and can hunt other animals.