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So it's now time for you to start writing some of your own Javascript functions.

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So I've written a problem set with three different problems.

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Each one you'll have to write your own javascript function.

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So I'm going to introduce all three problems and then in the next video we'll have solutions.

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So the first one is called is even.

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So you'll need to write a function called is even which takes a single argument which is a number and

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it returns true if the number is even and false if it's not.

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So there's a few examples is even of four returns true is even if 21 returns false is even a 68 is true

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3 3 3 is false.

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If you need to jog your memory on how you determine if a number is even you can watch some of the previous

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videos where we talked about modulo.

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Next up is a function called factorial.

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So most of you probably don't remember what factorial is.

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I think we talked about it like once in my high school math class.

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Basically you take a number like four and factorial is written with an exclamation point often.

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So for factorial is equal to 4 times 3 times 2 times 1.

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So that gives us 24 6 factorial is six times five times four times three times 2 times 1.

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So basically you're going to write a function that takes a number and multiply that number by every

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integer below that between that number and 1.

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So there's one small caveat which is zero factorial is 1.

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So to write this function in need to have a variable that you're constantly multiplying by smaller and

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smaller numbers so you multiply by four then three and then two and then one and you'll stop.

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When you multiply by 1.

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So you can see a few examples here.

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Factorial of five is five times four times three times two times one which is a 120 factorial of two

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is just two factorial of 10.

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Is this massive number and factorial of zero.

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Remember it needs to return 1.

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So the last one here is a little bit different.

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It's called Khabab to snake.

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So if you recall there are different ways of writing strings different cases.

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There's snake case where we use underscores like you see here.

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Hello underscore world.

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There's Khabab case where we use dashes haloed dash world.

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So you're going to write a function called Khabab to snake which takes a single string argument that

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is going to be Khabab case.

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So it uses dashes between words and your job is to replace all those dashes with underscores to make

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it snake case.

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So in order to do that you may need to research a little bit about how you can replace characters in

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a string.

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So it's definitely intentional that this one is last in the problems that you may need to do a little

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bit of research.

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Do some googling figure out how you can replace all of a specific character in a string with another

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specific character so you can see some sample input and output.

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Hello Dasch world.

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When you pass it into Khabab to snake should return Hello underscore world.

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And one key point about all these exercises.

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No contact logs.

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These are all returned statements.

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OK so in the next video we'll go over some solutions.