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Welcome to the first coding challenge 2

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of this section. 3

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And as you can imagine, 4

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this one is gonna be all about functions. 5

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And we're back to the two gymnastic teams 6

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from the previous section, the Dolphins and Koalas. 7

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And now there is a new gymnastics discipline 8

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which works in a bit different way. 9

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So now in this new discipline, 10

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each team competes three times 11

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and then the average of the three scores is calculated, 12

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so each team will get one average score. 13

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And then a team only wins 14

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if it has at least doubled the average score 15

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of the other team and otherwise no team wins. 16

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So sounds pretty simple, I hope. 17

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And let's take a look at your tasks now. 18

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So first create an arrow function 19

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called calcAverage which calculates the average 20

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of three scores. 21

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And actually this calcAverage function 22

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should be able to calculate the average of any three values. 23

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So of course, the values don't have to be scores. 24

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Any random numbers will work just the same. 25

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So this is basically a generic function 26

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just to calculate the average of three values. 27

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Then use that function 28

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to calculate the average for both teams. 29

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And again, down here, 30

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you have the test data that you can use. 31

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Create a function called checkWiner 32

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which takes the average score of each team as parameters, 33

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and these parameters 34

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should be called average Dolphins here and average Koalas. 35

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And then based on these two average scores, 36

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the function will log the winner to the console 37

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together with the victory points. 38

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And that of course needs to happen according to the rule 39

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that I just explained before. 40

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So a team only wins 41

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if it has at least doubled the average score 42

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of the other team, 43

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and otherwise no team wins. 44

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So you need to check for that condition 45

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in order to print which team wins, 46

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and in some cases, no team might win at all. 47

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So you need to account for that as well. 48

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So here in point three you write to checkWiner function 49

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and then a number four you will use. 50

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So basically you will call the checkWinner function 51

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in order to determine the winner 52

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for both to test data one and test data two. 53

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I have some hints again, 54

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but if you want to try it on your own without the hints 55

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then just past the video right now. 56

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But if you need to hints 57

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then well, here they go. 58

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So this one is probably pretty obvious 59

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which is to calculate the average of three values, 60

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add them altogether and divide by three. 61

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But the second one here is a little bit more important 62

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and maybe more difficult for you to figure out on your own. 63

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So to check if number A is at least double number B, 64

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what you need to check is if A 65

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is greater or equal two times B. 66

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And so this is what you will use 67

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with the teams average scores. 68

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So it's important to keep this one in mind 69

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because of this rule, 70

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that the team only wins when it has doubled average score 71

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of the other team. 72

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Now, please make really sure 73

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that you understood everything I showed you about functions 74

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before you attempt this challenge. 75

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Because this one is not so straight forward, 76

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and so I don't want you to get frustrated. 77

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So again, please really make sure you understand functions 78

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and only then attempt to do this challenge. 79

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But if you feel that you're ready, 80

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then just pause the video now 81

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and good luck with this challenge. 82

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Let me show you my solution to this challenge, 83

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which I hope of course you were able to do on your own. 84

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So I'm gonna start 85

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with the calcAverage function as a number one, 86

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and remember that this should be an arrow function 87

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and it will receive three values 88

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so that it can calculate the average 89

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of these three numbers. 90

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And here I'm actually just gonna call 91

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the three numbers, A, B and C, 92

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because again, this is supposed to be just 93

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a generic function which can calculate averages 94

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of any three numbers, 95

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it doesn't have to be any scores. 96

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And so A, B, C are just generic variable names. 97

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But of course it's totally okay 98

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if you used more specific variable names. 99

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So adding all the three numbers together 100

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and then dividing by three. 101

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So this one is nothing new, 102

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this was just to basically test your knowledge 103

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of the syntax of the arrow function. 104

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So what's important to notice here 105

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is that we need to parenthesis here 106

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because we have multiple parameters, 107

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but then here, we only really have this line of code. 108

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And so therefore we don't need to even write the return. 109

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This value gets automatically returned from the function. 110

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And now let's just test it out 111

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before we move any further. 112

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So calcAverage and then let's just use some random numbers 113

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because here we know that this is supposed to be four. 114

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So we have three, four, five. 115

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And so the middle one here 116

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is the average between these three. 117

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And indeed it is, and so we know that our function works. 118

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And so we can move on to point number two, 119

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which is to use the function 120

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to calculate the average for both teams. 121

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So let's say score Dolphins 122

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is equal to calcAverage 123

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and now we pass into specific arguments 124

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for the three parameters, A, B and C. 125

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And so for test data one, which is this, 126

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so let me actually write that here, test one. 127

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So for the Dolphins, we pass into values 44, 23 and 71. 128

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Then for the Koalas, it works the same way. 129

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So score Koalas equals calcAverage. 130

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And now we have 65, 54 and 49. 131

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Nice reusable function right here. 132

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And so having this function, 133

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we don't need to calculate it here manually 134

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every single time. 135

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So that's really great. 136

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We can really appreciate the fact that again, 137

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a function is really like a machine in some sense. 138

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So it doesn't care where the inputs come from 139

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and where they go. 140

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All it does is to calculate the average of three numbers, 141

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no matter if it's scores or heights of people 142

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or money or whatever it is. 143

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So this function really is kind of isolated 144

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from the rest of the code here. 145

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It's a standalone function that we can then use 146

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for our own purposes. 147

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And that might sound pretty obvious, 148

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but it's actually important that you really internalize 149

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this aspect of functions. 150

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Only then can you really start 151

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to see the potential for functions everywhere in your code. 152

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Anyway, with that being said, 153

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let's now log these values to the console 154

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'cause I always like to see what I'm doing. 155

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So this part is of course not mandatory, 156

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but it's also nice to be able to know the scores 157

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so that we know if the logic 158

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that we're gonna implement next is working correctly. 159

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So we see that in this case, 160

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the Koalas have a score that is higher 161

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than one of the Dolphins but it's not double. 162

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And so we already know that in this case 163

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no team should be able to win, 164

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but let's not actually implement that functionality. 165

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So that's the function checkWinner. 166

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And so it takes the average Dolphins 167

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and average Koalas parameters 168

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and then it locks the winner to the console. 169

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So let's do that. 170

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And what's more, it's no problem 171

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if you did this differently. 172

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If you made it work then it's great. 173

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So average Dolphins and average Koalas. 174

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And now all they need to do is to check 175

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whether the Dolphins won or the Koalas won 176

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or if no one won basically. 177

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So when do the Dolphins win? 178

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Well, they win 179

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if they have doubled the points of the Koalas, 180

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that's the condition. 181

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So again, a team only wins 182

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if it has at least doubled the average score 183

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of the other team. 184

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And so that's why I told you here in this hint 185

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that this is how we check for that. 186

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So A has double the amount of points of B 187

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if A is greater than two times B. 188

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So let's do that. 189

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So average Dolphins greater 190

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or equal to two times the average Koalas. 191

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And in this case, we look to the console 192

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Dolphins win the trophy, 193

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let's use an emoji here again 194

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but you don't need of course to do that. 195

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So it's already here, 196

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and now it also told us to put the points. 197

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For example, 30 versus 13, 198

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so both points with the versus in between. 199

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So that's average Dolphins 200

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versus average Koalas. 201

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So you'll see that here 202

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we are also practicing all the other skills 203

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that we already acquired before. 204

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Especially in the previous section. 205

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Then now here we need to just need to do the opposite. 206

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So else if, 207

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and now if the Koalas half at least. 208

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So that's basically what this one here means. 209

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So greater equal is basically at least. 210

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So if average Koalas 211

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have at least double the points of the Dolphins, 212

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then the Koalas win. 213

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So that's just grab this one from here. 214

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Koalas and tier it's average Koalas, 215

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and then average Dolphins, average, yes. 216

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And now in any other case, 217

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we say that no one wins. 218

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So I think that's also said in the rules. 219

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Yeah, that's a number of five. 220

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I think I even forgot to tell you this one 221

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but hopefully you read it. 222

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So you should ignore draws in this exercise this time. 223

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So if none of these is true, 224

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we simply say that no team wins. 225

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No team wins. 226

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And now all we need to do is to call this function here. 227

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So checkWinner, and we will do that 228

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with score Dolphins 229

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and score Koalas. 230

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Let's recap, we calculated the score of the Dolphins up here 231

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and of the Koalas as well. 232

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And now we call the checkWiner function here 233

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and we use as arguments 234

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the scores that we calculated before 235

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and then score Dolphins will become average Dolphins 236

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here in this function, 237

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because that's the name of the parameter. 238

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And I see that I misspelled this, 239

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and so now I can use that command D 240

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that I talked to you about before, 241

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so I can select all of them. 242

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So command D, command D,command D, command D 243

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and now I can use all of these cursors here 244

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at the same time. 245

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So Dolphins you see, 246

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I inserted the P in all of the variable names everywhere. 247

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And so now this parameter name here gets used 248

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for all these calculations. 249

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And again, originally this value comes basically from here, 250

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from calculating the average of these three scores. 251

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So this average gets stored here 252

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then we use it here 253

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and then it gets basically transferred to average Dolphins 254

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and is then used everywhere in this function. 255

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So let's now test. 256

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And as we expected, no team wins 257

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because this team here 258

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even though it has more than the Dolphins, it's not double. 259

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And so therefore they do not win. 260

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Now of course, what is also important to mention here 261

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is that this checkWiner function here 262

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is also completely independent of these score values 263

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that we calculated earlier. 264

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So here we can simply call this function 265

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with completely different values. 266

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So the function doesn't care 267

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where do these values come from. 268

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So where average Dolphins and average Koalas come from. 269

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It's a standalone function 270

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and it doesn't care at all, where it is values came from. 271

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We can just plug in some random numbers here 272

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and then call it and let's use a smaller number here. 273

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So just to that, the average Dolphin here 274

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is actually more than double of the average Koalas. 275

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So if you run this now, 276

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then we see that the Dolphins win with 576 versus 111. 277

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And so that's exactly the numbers 278

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that we plugged in in here. 279

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So once more, it's important to keep in mind 280

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that these functions are all independent from another. 281

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We just happen to call checkWiner here 282

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with these values that we calculated before, 283

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but it's not mandatory to do that, 284

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any other values will work just as well. 285

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And so we proved that here. 286

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Anyway, now let's use test data two, 287

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and actually what I'm gonna do 288

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is to reassign these two scores here. 289

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So we calculate them first, 290

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then we call checkWinner 291

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and then I'm going to recalculate them 292

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and call checkWinner again. 293

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What I mean by saying that 294

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is that these need to be let variables 295

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so that we can reassign them, remember that? 296

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Const values cannot be mutated, 297

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they cannot be changed, 298

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and so they need to be let. 299

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And then here, of course, we need to get rid of the let, 300

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because we do not want to create new variables, 301

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we just want to overwrite. 302

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So we want to reassign 303

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the values that we had earlier. 304

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So this time the values 305

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are 85, 54 and 41. 306

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85, 54 and 41. 307

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And I hope that's correct. 308

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And then for the Koalas, 309

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we have 23, 34 and 27. 310

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So that's 23, 34 and 27. 311

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Let's lock these actually also, 312

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and then simply call checkWinner again, 313

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and now with the new values 314

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of score Dolphins and score Koalas that we just reassigned. 315

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So let's see. 316

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And now the Dolphins seven average score of 60 317

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and to Koalas of 28. 318

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And so now the Dolphins win 319

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with a 60 versus 28. 320

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So that's a close call. 321

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So if the Koalas had three more points 322

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then no one would win, 323

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but the Dolphins managed to do it. 324

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Great, I hope that this all made sense to you, 325

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and I know it is probably still 326

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a bit confusing at this point. 327

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And if you did some things differently 328

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well then once more data's completely okay. 329

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It just means you're developing 330

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your own coding style over time. 331

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For example, here with the average scores, 332

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of course you could have created new variables down here 333

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for the test data too. 334

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So that's just one of many things 335

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that you could have done differently 336

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which are perfectly fine. 337

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As long as your results are the same, you're good to go. 338

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So take some time and review this lecture. 339

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Remember that you can check out my final code 340

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also in the final folder and the GitHub repo, 341

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and then you're ready to move on to our next big topic 342

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in the section, 343

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which is gonna be arrays. 344

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So I hope to see you there soon.