WEBVTT 1 00:00:00.300 --> 00:00:05.300 So let me show you my solution to this challenge 2 00:00:05.430 --> 00:00:09.330 which I hope of course, you were able to do on your own. 3 00:00:09.330 --> 00:00:12.540 So I'm gonna start with the calc average function, 4 00:00:12.540 --> 00:00:14.163 as in number one. 5 00:00:15.150 --> 00:00:17.880 And remember that this should be an arrow function, 6 00:00:17.880 --> 00:00:20.250 and it will receive three values, 7 00:00:20.250 --> 00:00:24.600 so that it can calculate the average of these three numbers. 8 00:00:24.600 --> 00:00:27.240 And here, I'm actually just gonna call the three numbers, 9 00:00:27.240 --> 00:00:32.190 A, B, and C, because again, 10 00:00:32.190 --> 00:00:35.280 this is supposed to be just a generic function 11 00:00:35.280 --> 00:00:38.850 which can calculate averages of any three numbers. 12 00:00:38.850 --> 00:00:40.830 It doesn't have to be any scores. 13 00:00:40.830 --> 00:00:44.670 And so, A, B, C, are just generic, variable names, 14 00:00:44.670 --> 00:00:47.070 but of course, it's totally okay 15 00:00:47.070 --> 00:00:50.073 if you used more specific variable names. 16 00:00:51.840 --> 00:00:54.180 So adding all the three numbers together, 17 00:00:54.180 --> 00:00:56.340 and then dividing by three. 18 00:00:56.340 --> 00:00:57.810 So this one is nothing new. 19 00:00:57.810 --> 00:01:00.540 This was just to basically test your knowledge 20 00:01:00.540 --> 00:01:03.360 of the syntax of the arrow function. 21 00:01:03.360 --> 00:01:05.100 So what's important to notice here 22 00:01:05.100 --> 00:01:06.990 is that we need the parenthesis here 23 00:01:06.990 --> 00:01:09.600 because we have multiple parameters, 24 00:01:09.600 --> 00:01:12.840 but then here, we only really have this line of code. 25 00:01:12.840 --> 00:01:16.770 And so therefore, we don't need to even write the return. 26 00:01:16.770 --> 00:01:20.700 This value gets automatically returned from the function. 27 00:01:20.700 --> 00:01:24.810 And now, let's just test it out before we move any further. 28 00:01:24.810 --> 00:01:29.810 So calc average and then let's just use some random numbers 29 00:01:30.390 --> 00:01:32.880 because here we know that 30 00:01:32.880 --> 00:01:36.630 this is supposed to be four, right? 31 00:01:36.630 --> 00:01:38.100 So we have 3, 4, 5. 32 00:01:38.100 --> 00:01:41.280 And so the middle one here is the average 33 00:01:41.280 --> 00:01:43.023 between these three, 34 00:01:44.610 --> 00:01:46.230 and indeed it is. 35 00:01:46.230 --> 00:01:48.630 And so, we know that our function works. 36 00:01:48.630 --> 00:01:51.570 And so, we can move on to point number two 37 00:01:51.570 --> 00:01:53.760 which is to use the function to calculate 38 00:01:53.760 --> 00:01:55.923 the average for both teams. 39 00:01:57.420 --> 00:02:01.320 So let's say, 40 00:02:01.320 --> 00:02:06.320 score dolphins is equal to calc average. 41 00:02:08.160 --> 00:02:10.350 And now we passed in the specific arguments 42 00:02:10.350 --> 00:02:13.950 for the three parameters, A, B, and C. 43 00:02:13.950 --> 00:02:16.890 And so, for test data one, which is this, 44 00:02:16.890 --> 00:02:20.370 so let me actually write that here, test one. 45 00:02:20.370 --> 00:02:25.370 So for the dolphins, we pass in the values 44, 23, and 71. 46 00:02:28.560 --> 00:02:32.220 Then for the koalas, it works the same way. 47 00:02:32.220 --> 00:02:36.540 So score, koalas equals calc average, 48 00:02:36.540 --> 00:02:40.593 and now, we have 65, 54, 49 00:02:41.880 --> 00:02:43.293 and 49. 50 00:02:44.370 --> 00:02:47.613 So nice reusable function right here. 51 00:02:48.660 --> 00:02:50.970 And so, having this function, we don't need 52 00:02:50.970 --> 00:02:54.450 to calculate it here manually every single time. 53 00:02:54.450 --> 00:02:56.103 So that's really great. 54 00:02:56.940 --> 00:03:00.870 So we can really appreciate the fact that again, 55 00:03:00.870 --> 00:03:04.890 a function is really like a machine in some sense. 56 00:03:04.890 --> 00:03:07.530 So it doesn't care where the inputs come from 57 00:03:07.530 --> 00:03:09.360 and where they go. 58 00:03:09.360 --> 00:03:12.930 All it does is to calculate the average of three numbers, 59 00:03:12.930 --> 00:03:16.230 no matter if it scores or heights of people, 60 00:03:16.230 --> 00:03:18.900 or money, or whatever it is. 61 00:03:18.900 --> 00:03:21.540 So this function really is kind of isolated 62 00:03:21.540 --> 00:03:23.730 from the rest of the code here. 63 00:03:23.730 --> 00:03:25.320 It's a standalone function 64 00:03:25.320 --> 00:03:29.010 that we can then use for our own purposes. 65 00:03:29.010 --> 00:03:31.230 And that might sound pretty obvious, 66 00:03:31.230 --> 00:03:32.580 but it's actually important 67 00:03:32.580 --> 00:03:36.720 that you really internalize this aspect of functions. 68 00:03:36.720 --> 00:03:39.870 Only then can you really start to see the potential 69 00:03:39.870 --> 00:03:43.380 for functions everywhere in your coat. 70 00:03:43.380 --> 00:03:48.380 Anyway, with that being said, let's now log these values 71 00:03:48.600 --> 00:03:53.600 to the console 'cause I always like to see what I'm doing. 72 00:03:54.000 --> 00:03:56.373 So this part is of course not mandatory, 73 00:03:57.300 --> 00:04:00.120 but it's also nice to be able to know these scores, 74 00:04:00.120 --> 00:04:02.280 so that we know if the logic that we're 75 00:04:02.280 --> 00:04:05.163 gonna implement next is working correctly. 76 00:04:06.030 --> 00:04:08.730 So we see that in this case, 77 00:04:08.730 --> 00:04:11.490 the koalas have a score that is higher 78 00:04:11.490 --> 00:04:14.940 than one of the dolphins, but it's not double. 79 00:04:14.940 --> 00:04:17.550 And so, we already know that in this case, 80 00:04:17.550 --> 00:04:20.460 no team should be able to win, 81 00:04:20.460 --> 00:04:23.433 but let's now actually implement that functionality. 82 00:04:24.420 --> 00:04:27.270 So that's the function check winner. 83 00:04:27.270 --> 00:04:29.520 And so, it takes the average dolphins 84 00:04:29.520 --> 00:04:33.417 and average koalas parameters, okay? 85 00:04:33.417 --> 00:04:36.450 And then it locks the winner to the console. 86 00:04:36.450 --> 00:04:38.253 So let's do that. 87 00:04:39.510 --> 00:04:42.993 And once more, it's no problem if you did this differently. 88 00:04:45.120 --> 00:04:47.823 If you made it work, then it's great. 89 00:04:49.350 --> 00:04:54.350 So average dolphins and average koalas. 90 00:04:57.660 --> 00:04:59.850 And now, all we need to do is to check 91 00:04:59.850 --> 00:05:01.410 whether the dolphins won 92 00:05:01.410 --> 00:05:06.090 or the koalas won, or if no one won basically. 93 00:05:06.090 --> 00:05:08.880 So when do the dolphins win? 94 00:05:08.880 --> 00:05:11.750 Well, they win if they have doubled the points 95 00:05:11.750 --> 00:05:13.680 of the koalas right? 96 00:05:13.680 --> 00:05:14.730 That's the condition. 97 00:05:16.260 --> 00:05:18.960 So again, a team only wins if it has 98 00:05:18.960 --> 00:05:22.410 at least double the average score of the other team. 99 00:05:22.410 --> 00:05:25.980 And so, that's why I told you here in this hint 100 00:05:25.980 --> 00:05:27.783 that this is how we check for that. 101 00:05:28.890 --> 00:05:32.760 So A has doubled the amount of point of B 102 00:05:32.760 --> 00:05:35.583 if A is greater than two times B. 103 00:05:37.140 --> 00:05:39.123 So let's do that. 104 00:05:40.920 --> 00:05:45.000 So average dolphins greater or equal 105 00:05:45.000 --> 00:05:50.000 to two times the average koalas. 106 00:05:50.820 --> 00:05:53.883 And in this case, we log to the console. 107 00:05:57.660 --> 00:06:01.110 Dolphins win the trophy. 108 00:06:01.110 --> 00:06:02.883 So let's use an emoji here, again, 109 00:06:03.720 --> 00:06:06.240 but you don't need of course to do that. 110 00:06:06.240 --> 00:06:07.413 So it's already here. 111 00:06:08.640 --> 00:06:12.390 And now, it also told us to put the points. 112 00:06:12.390 --> 00:06:17.353 So for example, 30 versus 13. 113 00:06:19.260 --> 00:06:22.410 So both points with the versus in between. 114 00:06:22.410 --> 00:06:27.410 So that's average dolphins versus average koalas. 115 00:06:32.820 --> 00:06:35.760 So you see that here, we are also practicing all 116 00:06:35.760 --> 00:06:39.360 the other skills that we already acquired before, 117 00:06:39.360 --> 00:06:41.973 especially in the previous section, right? 118 00:06:43.620 --> 00:06:46.980 Okay. And now here, we gonna just need to do the opposite. 119 00:06:46.980 --> 00:06:51.540 So else if and now 120 00:06:51.540 --> 00:06:55.320 if the koalas have at least, 121 00:06:55.320 --> 00:06:58.380 so that's basically what this one here means. 122 00:06:58.380 --> 00:07:01.770 So greater equal is basically at least. 123 00:07:01.770 --> 00:07:05.260 So if average koalas have at least double the points 124 00:07:06.300 --> 00:07:11.300 of the dolphins, then the koalas win. 125 00:07:11.700 --> 00:07:14.433 So let's just grab this one from here, 126 00:07:15.780 --> 00:07:16.713 koalas, 127 00:07:19.650 --> 00:07:20.640 average koalas, 128 00:07:20.640 --> 00:07:24.003 and then average dolphins, 129 00:07:25.500 --> 00:07:26.883 average, yes. 130 00:07:27.840 --> 00:07:31.410 All right, and now, in any other case, 131 00:07:31.410 --> 00:07:33.990 we say that no one wins. 132 00:07:33.990 --> 00:07:36.273 So I think that's also said in the rules. 133 00:07:37.470 --> 00:07:39.360 Yeah, that's number five. 134 00:07:39.360 --> 00:07:42.480 I think I even forgot to tell you this one, 135 00:07:42.480 --> 00:07:44.250 but hopefully you read it. 136 00:07:44.250 --> 00:07:49.250 So you should ignore draws in this exercise this time. 137 00:07:50.220 --> 00:07:51.810 So if none of these is true, 138 00:07:51.810 --> 00:07:53.763 we simply say that no team wins. 139 00:07:57.030 --> 00:08:00.153 No team wins. 140 00:08:01.770 --> 00:08:02.760 Okay. 141 00:08:02.760 --> 00:08:06.663 And now, all we need to do is to call this function here. 142 00:08:07.560 --> 00:08:11.520 So check winner, and we will do that 143 00:08:11.520 --> 00:08:13.570 with score dolphins 144 00:08:14.610 --> 00:08:18.063 and score koalas. 145 00:08:19.140 --> 00:08:21.930 Okay? So let's recap. 146 00:08:21.930 --> 00:08:23.160 We calculated the score 147 00:08:23.160 --> 00:08:27.090 of the dolphins up here and of the koalas as well. 148 00:08:27.090 --> 00:08:32.090 And now, we call the check winner function here, okay? 149 00:08:32.100 --> 00:08:33.600 And we use as arguments, 150 00:08:33.600 --> 00:08:36.150 the scores that we calculated before. 151 00:08:36.150 --> 00:08:39.670 And then, score dolphins will become average dolphins 152 00:08:41.160 --> 00:08:42.330 here in this function 153 00:08:42.330 --> 00:08:44.760 because that's the name of the parameter. 154 00:08:44.760 --> 00:08:46.950 And I see that I misspelled this, 155 00:08:46.950 --> 00:08:50.310 and so, now I can use that command D that I talked 156 00:08:50.310 --> 00:08:53.370 to you about before, so I can select all of them. 157 00:08:53.370 --> 00:08:54.750 So command D, command D, 158 00:08:54.750 --> 00:08:58.230 command D, command D, and now I can use all 159 00:08:58.230 --> 00:09:00.660 of these cursors here at the same time. 160 00:09:00.660 --> 00:09:01.713 So dolphins. 161 00:09:03.810 --> 00:09:06.390 You see? I inserted the P in all 162 00:09:06.390 --> 00:09:08.943 of the variable names everywhere. 163 00:09:10.980 --> 00:09:12.330 Now, all right? 164 00:09:12.330 --> 00:09:15.630 And so, now this parameter name here gets used 165 00:09:15.630 --> 00:09:17.940 for all these calculations. 166 00:09:17.940 --> 00:09:22.170 And again, originally, this value comes basically from here, 167 00:09:22.170 --> 00:09:26.040 from calculating the average of these three scores. 168 00:09:26.040 --> 00:09:30.180 So this average gets stored here, then we use it here, 169 00:09:30.180 --> 00:09:34.020 and then it gets basically transferred to average dolphins, 170 00:09:34.020 --> 00:09:36.423 and is then used everywhere in this function. 171 00:09:37.680 --> 00:09:40.080 Okay? So let's now test. 172 00:09:40.080 --> 00:09:44.580 And as we expected, no team wins because this team here, 173 00:09:44.580 --> 00:09:48.510 even though it has more than the dolphins, it's not double. 174 00:09:48.510 --> 00:09:50.493 And so therefore, they do not win. 175 00:09:51.360 --> 00:09:54.660 Now of course, what is also important to mention here 176 00:09:54.660 --> 00:09:57.960 is that this check winner function here 177 00:09:57.960 --> 00:10:00.390 is also completely independent 178 00:10:00.390 --> 00:10:04.410 of these score values that we calculated earlier. 179 00:10:04.410 --> 00:10:07.440 So here, we can simply call this function 180 00:10:07.440 --> 00:10:09.510 with completely different values. 181 00:10:09.510 --> 00:10:12.810 So the function doesn't care where these values come from, 182 00:10:12.810 --> 00:10:16.560 so where average dolphins and average koalas come from. 183 00:10:16.560 --> 00:10:18.240 It's a standalone function, 184 00:10:18.240 --> 00:10:21.360 and it doesn't care at all where these values came from. 185 00:10:21.360 --> 00:10:23.560 We can just plug in some random numbers here 186 00:10:25.140 --> 00:10:29.040 and then call it, and let's use a smaller number here. 187 00:10:29.040 --> 00:10:32.310 Okay, so just so that the average dolphin here 188 00:10:32.310 --> 00:10:35.223 is actually more than double of the average koalas. 189 00:10:36.120 --> 00:10:38.490 So if you run this now, 190 00:10:38.490 --> 00:10:43.490 then we see that the dolphins win with 576 versus 111. 191 00:10:44.760 --> 00:10:46.530 And so, that's exactly the numbers 192 00:10:46.530 --> 00:10:50.400 that we plugged in in here, okay? 193 00:10:50.400 --> 00:10:53.190 So once more, it's important to keep in mind 194 00:10:53.190 --> 00:10:56.310 that these functions are all independent from another. 195 00:10:56.310 --> 00:10:59.010 We just happen to call check winner here 196 00:10:59.010 --> 00:11:01.500 with these values that we calculated before, 197 00:11:01.500 --> 00:11:03.600 but it's not mandatory to do that. 198 00:11:03.600 --> 00:11:06.810 Any other values will work just as well. 199 00:11:06.810 --> 00:11:08.193 And so, we prove that here. 200 00:11:09.210 --> 00:11:13.020 Anyway, now, let's use test data 2. 201 00:11:13.020 --> 00:11:14.460 And actually what I'm gonna do is 202 00:11:14.460 --> 00:11:17.850 to reassign these two scores here. 203 00:11:17.850 --> 00:11:21.840 So we calculate them first, then we call check winner, 204 00:11:21.840 --> 00:11:24.240 and then I'm going to recalculate them 205 00:11:24.240 --> 00:11:26.670 and call check winner again. 206 00:11:26.670 --> 00:11:30.240 So what I mean by saying that is that these need 207 00:11:30.240 --> 00:11:34.470 to be let variables, so that we can reassign them. 208 00:11:34.470 --> 00:11:39.060 Remember that cons values cannot be mutated. 209 00:11:39.060 --> 00:11:43.710 They cannot be changed, and so they need to be let. 210 00:11:43.710 --> 00:11:46.740 And then here, of course, we need to get rid of 211 00:11:46.740 --> 00:11:50.550 that let because we do not want to create new variables. 212 00:11:50.550 --> 00:11:52.260 We just want to overwrite. 213 00:11:52.260 --> 00:11:55.893 So we want to reassign the values that we had earlier. 214 00:11:57.510 --> 00:12:00.863 So this time, the values are 85, 54, and 41. 215 00:12:07.710 --> 00:12:12.710 85, 54, and 41, 216 00:12:12.840 --> 00:12:14.880 and I hope that's correct, 217 00:12:14.880 --> 00:12:17.553 and then 40 koalas. 218 00:12:18.840 --> 00:12:22.413 We have 23, 34, and 27. 219 00:12:24.240 --> 00:12:29.053 So that's 23, 34, and 27. 220 00:12:31.650 --> 00:12:33.753 Let's lock these actually also. 221 00:12:34.710 --> 00:12:39.420 And then simply call check winner again. 222 00:12:39.420 --> 00:12:41.010 And now, with the new values 223 00:12:41.010 --> 00:12:43.590 of score dolphins and score koalas, 224 00:12:43.590 --> 00:12:46.833 they'll be just reassigned, okay? 225 00:12:47.820 --> 00:12:50.013 So let's see. 226 00:12:51.060 --> 00:12:53.070 And now, the dolphins have an average score 227 00:12:53.070 --> 00:12:55.800 of 60 and the koalas of 28. 228 00:12:55.800 --> 00:13:00.800 And so now, the dolphins win with 60 versus 28, 229 00:13:01.350 --> 00:13:03.450 so that's a close call. 230 00:13:03.450 --> 00:13:05.670 So if the koalas had three more points, 231 00:13:05.670 --> 00:13:07.230 then no one would win, 232 00:13:07.230 --> 00:13:09.633 but the dolphins managed to do it. 233 00:13:10.950 --> 00:13:15.950 Great. So I hope that this all made sense to you, 234 00:13:16.530 --> 00:13:18.720 and I know it is probably still 235 00:13:18.720 --> 00:13:21.390 a bit confusing at this point. 236 00:13:21.390 --> 00:13:23.520 And if you did some things differently, 237 00:13:23.520 --> 00:13:26.700 well then once more, that is completely okay. 238 00:13:26.700 --> 00:13:28.080 It just means you're developing 239 00:13:28.080 --> 00:13:31.290 your own coding style over time. 240 00:13:31.290 --> 00:13:34.110 For example, here with the average scores, 241 00:13:34.110 --> 00:13:37.440 of course, you could have created new variables down here 242 00:13:37.440 --> 00:13:39.510 for the test data 2. 243 00:13:39.510 --> 00:13:41.100 So that's just one of many things 244 00:13:41.100 --> 00:13:42.930 that you could have done differently 245 00:13:42.930 --> 00:13:44.400 which are perfectly fine. 246 00:13:44.400 --> 00:13:48.300 As long as your results are the same, you are good to go, 247 00:13:48.300 --> 00:13:51.390 so take some time and review this lecture. 248 00:13:51.390 --> 00:13:54.600 Remember that you can check out my final code also 249 00:13:54.600 --> 00:13:58.560 in the final folder, in the GitHub repo, 250 00:13:58.560 --> 00:14:02.790 and then you're ready to move on to our next big topic 251 00:14:02.790 --> 00:14:05.820 in the section, which is gonna be a race. 252 00:14:05.820 --> 00:14:07.833 So I hope to see you there soon.