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OK we'll come back.

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As I mentioned in the last video we have one more exercise just to get some more practice with the command

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line and running files with node as well as brushing up some of those basic javascript skills.

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So again I've typed up the instructions.

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Feel free to read them and just go over it on your own.

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But also walk through them step by step.

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So the first thing you need to do is create a new file called Greater Dot.

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Yes.

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The idea behind this exercise is that you are a teacher teaching a class and you have a bunch of test

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scores and they're in an array and you want to find the average score in the array.

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So you're going to define a new function called Average inside if the new file and that average function

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should take a single parameter an array of test scores which are all numbers between 0 and 100 and then

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the function should return the average score in the array.

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But it should be rounded to the nearest whole number so no.

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Ninety three point three four to one.

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Blah blah blah.

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It should just be 93.

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Here are two examples that you should copy into your code and make sure that they work.

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So the first one we have some scores that are a little higher.

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And the second one some more negative scores and the first one should return 94 and the second one should

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return 68.

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Just a hint about rounding to the nearest whole number.

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You don't need to do that yourself there's no fancy logic you need to do.

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There's actually a special method on the math object that will help you.

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So do a little research on that as always puzzle video.

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Give this a shot and I'll be back with a solution.

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OK let's get started.

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First of all we need to make a new file called Greater us just like that.

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Make sure it worked.

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There it is greater dot J us and then we need to define a function average and average should take an

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array of scores.

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So we'll just call it scores and I'm going to copy these two test cases to the very bottom just so I

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have them.

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So we pass in an array of numbers and to find the average of something we're going to need to take every

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element and added together and then we'll need to divide by the number of elements so that can be first

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add all scores together and then next would be divide by total number of scores.

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And then lastly round OK to add all the scores together we need to loop through the array and have a

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variable that we're adding each number to.

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And this is something called the accumulator pattern where we have a variable that is going to accumulate

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something as we iterate through an array or collection.

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So in this case it will accumulate a total.

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So we'll find a variable called Total and started at zero.

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Then we loop through scores.

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So to do that we could use a for loop a while loop.

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Or my favorite A for each.

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So I'll do a for each scores dot for each function and we'll just call it score as our placeholder variable

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.

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Each one of these is going to be named score and then we'll just do a total plus equals score.

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So this would work to go through the array and it adds everything together.

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The next thing that we need to do is divide by the total number of scores to do that.

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Let's make another variable called Average HEG equals total divided by and the number of scores is just

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scores of length.

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And then the last thing here is to round it which is math dot round.

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And we want to round a Viji and return that just like that math that round is one of those built in

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methods like math floor or math dot Rand.

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And unlike math top floor which we'll just chop off the decimal point math that round we'll round up

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or down depending on the decimal.

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OK so let's work through this again.

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We pass in an array.

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It's called scores.

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We start a total variable at zero.

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We loop through the scores using a for each in this case but we could use any any other type of loop

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.

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And then we add each score into the total and then we divide the total by all the scores scores that

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length and that set that equal to the variable average and then we math round average and then we return

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that.

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So if we run this now save and rerun node that greater or node greater dot J Yes we have a small problem

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not with our logic but in that we have no idea if this worked.

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And that's of course because we're only returning something.

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I never told you to actually print anything out.

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So what we could do is either cancel that log.

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This here that's probably the best way.

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So that we don't actually change our function.

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It still returns and we'll just cancel that log.

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The result just like that.

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There's the first one.

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And now a constant log.

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The second one and we're hoping to get 94 and 68 and let's add a message here to make it clear so Consta

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that log this will be average score for and phi and mental science which I took it was extremely easy

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.

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The average was probably higher than 94.

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And then I'll do another one here.

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Cancel that log average score.

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And this will be for organic chemistry where the average score on a test was probably much lower than

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68.

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So let's save and now run that again just hit the up arrow and hit enter and we get 94 which is what

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we expected.

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And 68 which is also what we expected.

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So that's it for these quick exercises.

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The next thing we're going to do is learn about something called NPM node package manager.

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And that will put us one step closer to writing our server side logic and making full stack web applications

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.

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Right now we're just writing these simple functions instead of a file and running them.

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But once we learn more about NPM and talk about some of the packages we're going to use we actually

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start writing full applications.