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These are the user uploaded subtitles that are being translated: 1 1 00:00:01,070 --> 00:00:02,480 It's now finally time 2 2 00:00:02,480 --> 00:00:05,130 for your very first coding challenge. 3 3 00:00:05,130 --> 00:00:08,970 So coding challenges are basically coding exercises 4 4 00:00:08,970 --> 00:00:11,170 that you have to code on your own, 5 5 00:00:11,170 --> 00:00:13,700 and they are super important for you to test 6 6 00:00:13,700 --> 00:00:15,820 and reinforce all the skills 7 7 00:00:15,820 --> 00:00:17,680 that you just learned before. 8 8 00:00:17,680 --> 00:00:20,610 That's why there are dozens of coding challenges 9 9 00:00:20,610 --> 00:00:24,560 in this course, because students love them and they are one 10 10 00:00:24,560 --> 00:00:26,883 of the best ways of learning. 11 11 00:00:28,420 --> 00:00:31,070 And so this is the coding challenge number one 12 12 00:00:31,070 --> 00:00:33,790 of the section or coding exercise 13 13 00:00:33,790 --> 00:00:36,640 if you prefer to call it that. 14 14 00:00:36,640 --> 00:00:39,150 Now all of these coding challenges are also 15 15 00:00:39,150 --> 00:00:40,760 in a separate PDF file 16 16 00:00:40,760 --> 00:00:42,540 that is available somewhere 17 17 00:00:42,540 --> 00:00:43,700 in the course. 18 18 00:00:43,700 --> 00:00:46,300 So you can also get this text from there. 19 19 00:00:46,300 --> 00:00:49,030 You don't have to read the video. 20 20 00:00:49,030 --> 00:00:53,130 Okay. Now, anyway, the exercise is this 21 21 00:00:53,130 --> 00:00:54,760 Mark and John are trying 22 22 00:00:54,760 --> 00:00:59,070 to compare their body mass indexes and the BMI 23 23 00:00:59,070 --> 00:01:02,200 is calculated using this formula. 24 24 00:01:02,200 --> 00:01:07,200 So BMI is equal to mass divided by the height squared. 25 25 00:01:07,490 --> 00:01:08,709 Okay. 26 26 00:01:08,709 --> 00:01:11,690 And so squared is the exponentiation operator that we talked 27 27 00:01:11,690 --> 00:01:14,410 about before with the two. 28 28 00:01:14,410 --> 00:01:15,243 Okay. 29 29 00:01:15,243 --> 00:01:16,730 And so that is also the same 30 30 00:01:16,730 --> 00:01:20,880 to mass equals height times height. 31 31 00:01:20,880 --> 00:01:21,713 Okay. 32 32 00:01:21,713 --> 00:01:25,560 So this part is the same as this one. 33 33 00:01:25,560 --> 00:01:26,393 So you can choose 34 34 00:01:26,393 --> 00:01:29,140 to calculate the BMI either way. 35 35 00:01:29,140 --> 00:01:31,730 Now, what matters is that a mass needs to be 36 36 00:01:31,730 --> 00:01:35,490 in kilograms and to height needs to be in meters. 37 37 00:01:35,490 --> 00:01:36,920 So it's not gonna work 38 38 00:01:36,920 --> 00:01:40,710 with the U.S measures like feet and pound, 39 39 00:01:40,710 --> 00:01:43,560 but that's why I have the test data here already 40 40 00:01:43,560 --> 00:01:46,220 with the correct measurements. 41 41 00:01:46,220 --> 00:01:49,540 Anyway, here is what I want you to do for this challenge. 42 42 00:01:49,540 --> 00:01:52,850 One, you should store mark's and John's mass 43 43 00:01:52,850 --> 00:01:54,840 and height in variables, 44 44 00:01:54,840 --> 00:01:57,780 and you should do this for test data one. 45 45 00:01:57,780 --> 00:01:59,500 So this data here 46 46 00:01:59,500 --> 00:02:03,500 and then also for test data two, all right, 47 47 00:02:03,500 --> 00:02:06,830 then using these variables calculate both 48 48 00:02:06,830 --> 00:02:10,350 their BMI's using the formula that I just showed you. 49 49 00:02:10,350 --> 00:02:12,470 And again, you can use either one, 50 50 00:02:12,470 --> 00:02:14,530 it's gonna work the same way. 51 51 00:02:14,530 --> 00:02:17,510 Of course, to then check these values if they make sense, 52 52 00:02:17,510 --> 00:02:18,980 you can log them to the console, 53 53 00:02:18,980 --> 00:02:22,100 just like we have been doing up until this point. 54 54 00:02:22,100 --> 00:02:23,730 Then finally, I want you 55 55 00:02:23,730 --> 00:02:27,197 to create a Boolean variable called 'markHigherBMI', 56 56 00:02:28,510 --> 00:02:30,300 which will contain the information, 57 57 00:02:30,300 --> 00:02:33,760 whether Mark has a higher BMI than John. 58 58 00:02:33,760 --> 00:02:34,593 Okay. 59 59 00:02:34,593 --> 00:02:36,450 And this is actually similar to something 60 60 00:02:36,450 --> 00:02:38,520 that we did before So I hope that 61 61 00:02:38,520 --> 00:02:41,340 you can make this one work just fine. 62 62 00:02:41,340 --> 00:02:45,700 So now please really try to solve this problem on your own. 63 63 00:02:45,700 --> 00:02:47,470 And remember the advice that I gave you 64 64 00:02:47,470 --> 00:02:48,770 in the beginning. 65 65 00:02:48,770 --> 00:02:51,950 Don't try to make this perfect for now. 66 66 00:02:51,950 --> 00:02:54,670 What matters is really just to make it work. 67 67 00:02:54,670 --> 00:02:56,700 It doesn't matter if you write clean code 68 68 00:02:56,700 --> 00:02:59,720 or perfect code or efficient code, 69 69 00:02:59,720 --> 00:03:01,370 just make it work for now. 70 70 00:03:01,370 --> 00:03:02,500 All right. 71 71 00:03:02,500 --> 00:03:04,980 So pause the video now And I see you 72 72 00:03:04,980 --> 00:03:07,113 in a second with the solution. 73 73 00:03:08,310 --> 00:03:09,143 All right. 74 74 00:03:10,072 --> 00:03:12,510 I hope you manage to complete all the three Points 75 75 00:03:12,510 --> 00:03:14,280 of this challenge. 76 76 00:03:14,280 --> 00:03:15,113 And so here is 77 77 00:03:15,113 --> 00:03:17,163 how I would have implemented it. 78 78 00:03:18,860 --> 00:03:22,480 So I'm starting with number one, of course. 79 79 00:03:22,480 --> 00:03:26,237 And so let's say const massMark equals 78. 80 80 00:03:32,030 --> 00:03:32,863 Okay. 81 81 00:03:32,863 --> 00:03:34,040 So that's just, 82 82 00:03:34,040 --> 00:03:34,983 what is written here. 83 83 00:03:36,160 --> 00:03:41,160 And then heightMark equals one 69 84 84 00:03:45,840 --> 00:03:48,270 and then the same for John. 85 85 00:03:48,270 --> 00:03:52,360 So massJohn equals 92 86 86 00:03:53,870 --> 00:03:58,870 and then heightJohn equals one 95 now, right? 87 87 00:04:01,880 --> 00:04:04,110 And if you used different variable names, 88 88 00:04:04,110 --> 00:04:06,040 that's not a problem at all. 89 89 00:04:06,040 --> 00:04:08,220 As long as they are nicely descriptive, 90 90 00:04:08,220 --> 00:04:09,740 like these ones here, 91 91 00:04:09,740 --> 00:04:10,960 you're going to be fine. 92 92 00:04:10,960 --> 00:04:14,840 Also, you might've used a let here instead of const, 93 93 00:04:14,840 --> 00:04:17,160 because you might assume that these are values that 94 94 00:04:17,160 --> 00:04:19,560 are susceptible to change, 95 95 00:04:19,560 --> 00:04:22,290 especially here the mass, all right. 96 96 00:04:22,290 --> 00:04:26,380 However, I still decided to use const because I already know 97 97 00:04:26,380 --> 00:04:28,840 that I'm not going to change these values here 98 98 00:04:28,840 --> 00:04:30,620 throughout the program. 99 99 00:04:30,620 --> 00:04:32,550 And so just as we learned before, 100 100 00:04:32,550 --> 00:04:35,810 I prefer to always use const by default 101 101 00:04:35,810 --> 00:04:37,220 and I advise you 102 102 00:04:37,220 --> 00:04:38,473 to actually do the same. 103 103 00:04:39,610 --> 00:04:40,690 Okay. 104 104 00:04:40,690 --> 00:04:44,820 Anyway, let's now calculate the actual BMIs. 105 105 00:04:44,820 --> 00:04:46,873 So const BMIMark 106 106 00:04:46,873 --> 00:04:51,740 equals massMark divided, 107 107 00:04:56,370 --> 00:04:58,680 and let's check out the formula again, 108 108 00:04:58,680 --> 00:05:01,550 divided by the height squared. 109 109 00:05:01,550 --> 00:05:04,623 So that's going to be heightMark squared 110 110 00:05:09,760 --> 00:05:13,737 and then the BMIJohn So that's massJohn, 111 111 00:05:17,470 --> 00:05:20,860 and this time let's actually use the other formula. 112 112 00:05:20,860 --> 00:05:22,553 So this one here. 113 113 00:05:23,890 --> 00:05:27,970 So we're gonna use, heightJohn times heightJohn again. 114 114 00:05:32,650 --> 00:05:33,670 Okay. 115 115 00:05:33,670 --> 00:05:36,300 And now let's log both of them 116 116 00:05:36,300 --> 00:05:37,483 to the console here. 117 117 00:05:38,400 --> 00:05:39,740 So BMIMark and BMIJohn. 118 118 00:05:47,730 --> 00:05:50,030 And now we have an error here. 119 119 00:05:50,030 --> 00:05:52,563 Oh, of course I missed the dot log. 120 120 00:05:54,140 --> 00:05:55,280 Okay. 121 121 00:05:55,280 --> 00:05:56,800 Try it again. 122 122 00:05:56,800 --> 00:05:58,383 And here we go. 123 123 00:05:59,795 --> 00:06:01,820 So we see that BMIMark is higher 124 124 00:06:03,440 --> 00:06:05,148 than John's BMI. 125 125 00:06:05,148 --> 00:06:06,720 Okay. 126 126 00:06:06,720 --> 00:06:07,553 So I hope you got the same numbers here 127 127 00:06:07,553 --> 00:06:08,760 than I did. 128 128 00:06:08,760 --> 00:06:10,470 And if not, 129 129 00:06:10,470 --> 00:06:11,780 I guess you should probably check 130 130 00:06:11,780 --> 00:06:14,840 your code unless I have some mistake here. 131 131 00:06:14,840 --> 00:06:16,313 Let me check that actually. 132 132 00:06:17,400 --> 00:06:20,150 But I think everything is good. 133 133 00:06:20,150 --> 00:06:20,983 Okay. 134 134 00:06:20,983 --> 00:06:21,990 So if something is wrong, 135 135 00:06:21,990 --> 00:06:23,950 then please just let me know. 136 136 00:06:23,950 --> 00:06:25,040 All right. 137 137 00:06:25,040 --> 00:06:26,650 Now, if you implemented this 138 138 00:06:26,650 --> 00:06:28,850 in a different way, for example, 139 139 00:06:28,850 --> 00:06:30,760 you might not have created 140 140 00:06:30,760 --> 00:06:33,420 these separate variables here, 141 141 00:06:33,420 --> 00:06:35,730 then that's not a problem at all. 142 142 00:06:35,730 --> 00:06:36,563 Okay. 143 143 00:06:36,563 --> 00:06:38,690 You could have logged these calculations straight 144 144 00:06:38,690 --> 00:06:39,650 to the console. 145 145 00:06:39,650 --> 00:06:41,380 No problem at all. 146 146 00:06:41,380 --> 00:06:44,800 Again, what matters here is that you make this work and 147 147 00:06:44,800 --> 00:06:45,920 that in the end you get 148 148 00:06:45,920 --> 00:06:47,633 these same results here. 149 149 00:06:49,440 --> 00:06:52,852 Anyway, let's now also do step three 150 150 00:06:52,852 --> 00:06:56,117 and create a variable called 'markHigherBMI'. 151 151 00:06:57,212 --> 00:06:59,597 So let's just grab this here and const. 152 152 00:07:03,970 --> 00:07:05,580 And so what we're trying to figure out 153 153 00:07:05,580 --> 00:07:10,580 is if the BMI of Mark is higher than the BMI of John, right? 154 154 00:07:16,010 --> 00:07:19,280 And so that's what comparison operators are for, 155 155 00:07:19,280 --> 00:07:23,670 because remember that this one here will return either true 156 156 00:07:23,670 --> 00:07:25,390 or false. 157 157 00:07:25,390 --> 00:07:26,470 In our example, 158 158 00:07:26,470 --> 00:07:31,140 if BMI Mark is larger than one of John, 159 159 00:07:31,140 --> 00:07:33,530 then the result of this 160 160 00:07:33,530 --> 00:07:35,980 whole operator here will be true 161 161 00:07:35,980 --> 00:07:38,230 and otherwise it's gonna be false. 162 162 00:07:38,230 --> 00:07:39,063 Okay. 163 163 00:07:39,063 --> 00:07:40,800 So that's exactly what we did before 164 164 00:07:40,800 --> 00:07:44,940 in this example with the ages 165 165 00:07:44,940 --> 00:07:46,970 if I remember correctly. 166 166 00:07:46,970 --> 00:07:51,810 So where's that? It's right here. 167 167 00:07:51,810 --> 00:07:55,010 In this case, it was 'isFullAge' variable. 168 168 00:07:55,010 --> 00:07:55,843 Right? 169 169 00:07:57,100 --> 00:07:58,290 Okay. 170 170 00:07:58,290 --> 00:08:01,593 Anyway, let's log to your tutor console as well. 171 171 00:08:02,940 --> 00:08:04,290 And so we expect this one 172 172 00:08:04,290 --> 00:08:07,060 to be true, right? 173 173 00:08:07,060 --> 00:08:11,910 Because Mark's BMI is 27 and John's is 24. 174 174 00:08:11,910 --> 00:08:15,510 And so Mark's is larger and so the result 175 175 00:08:15,510 --> 00:08:17,460 of this should be true. 176 176 00:08:17,460 --> 00:08:20,670 So let's check that and indeed, 177 177 00:08:20,670 --> 00:08:21,823 we get true. 178 178 00:08:22,680 --> 00:08:23,580 Nice. 179 179 00:08:23,580 --> 00:08:26,510 So we basically solved it. 180 180 00:08:26,510 --> 00:08:29,930 Now I just want to do the same here for test data too. 181 181 00:08:29,930 --> 00:08:31,223 So we'll just copy this. 182 182 00:08:32,190 --> 00:08:35,630 So copy, and then I will simply comment 183 183 00:08:35,630 --> 00:08:37,893 out these first ones. 184 184 00:08:39,890 --> 00:08:43,693 So now I'm replacing these with 95, 185 185 00:08:44,628 --> 00:08:48,310 one 88 and then here for John, 186 186 00:08:48,310 --> 00:08:52,723 we have 85 and one 76. 187 187 00:08:53,790 --> 00:08:54,960 And the rest of course 188 188 00:08:55,878 --> 00:08:56,988 is the same. 189 189 00:08:56,988 --> 00:08:58,660 And that's the beauty of using variables 190 190 00:08:58,660 --> 00:09:01,140 because now all we have to do is to change 191 191 00:09:01,140 --> 00:09:03,100 these values in one place 192 192 00:09:03,100 --> 00:09:06,010 and then the changes will be propagated to the rest 193 193 00:09:06,010 --> 00:09:08,010 of the code here, 194 194 00:09:08,010 --> 00:09:10,703 which references these variables. 195 195 00:09:12,640 --> 00:09:13,473 Cool. 196 196 00:09:13,473 --> 00:09:15,050 So let's reload. 197 197 00:09:15,050 --> 00:09:20,050 And now BMI of John is 27. 198 198 00:09:20,800 --> 00:09:24,810 So it's a larger than 26.8. 199 199 00:09:24,810 --> 00:09:28,318 It's actually very close, but still, 200 200 00:09:28,318 --> 00:09:30,850 BMIMark is now lower 201 201 00:09:30,850 --> 00:09:32,180 than BMIJohn. 202 202 00:09:32,180 --> 00:09:34,880 So here we asked the question basically 203 203 00:09:34,880 --> 00:09:36,840 is BMIMark a larger 204 204 00:09:36,840 --> 00:09:38,470 than BMIJohn? 205 205 00:09:38,470 --> 00:09:40,230 And in this case it's not. 206 206 00:09:40,230 --> 00:09:41,480 So it's false. 207 207 00:09:41,480 --> 00:09:43,320 And so that's exactly the result 208 208 00:09:43,320 --> 00:09:44,970 that we get here. 209 209 00:09:44,970 --> 00:09:45,920 All right? 210 210 00:09:45,920 --> 00:09:50,530 So this one is solved and I hope you solved it as well. 211 211 00:09:50,530 --> 00:09:52,620 Again, it does not matter at all, 212 212 00:09:52,620 --> 00:09:54,770 if you did it in a different way, 213 213 00:09:54,770 --> 00:09:57,170 as long as the results were the same. 214 214 00:09:57,170 --> 00:10:01,630 So basically as long as you actually made it work. 215 215 00:10:01,630 --> 00:10:04,650 So, hopefully that was a lot of fun 216 216 00:10:04,650 --> 00:10:07,350 and you could practice your skillset little bit, 217 217 00:10:07,350 --> 00:10:09,490 which is really something essential 218 218 00:10:09,490 --> 00:10:11,980 to learn programming properly, 219 219 00:10:11,980 --> 00:10:15,010 without repetition and reinforcing your knowledge 220 220 00:10:15,010 --> 00:10:18,620 It's impossible, really to learn how to code. 221 221 00:10:18,620 --> 00:10:21,010 Anyway, see you now in the next video 222 222 00:10:21,010 --> 00:10:24,404 where we're going to continue learning the fundamentals 223 223 00:10:24,404 --> 00:10:26,254 of the beautiful JavaScript language. 17642