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Before we go back to your classes, I would like to talk about something called scope and scope is an

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important concept that you need to understand in order for us to move forward with classes.

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So scope is the following.

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So let's say I'm creating a function here, and I'm going to call this one my function.

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And here I pass a value.

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Hey, which is of Typekit?

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OK.

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So if I now try to assign a value to my variable a it doesn't work because it's not really a variable.

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This is.

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A perimeter so you cannot assign a value to a perimeter within the function.

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You can only has an argument when calling the function.

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So here I can, for example, pass five as a.

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All right.

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So you cannot reassign a value to it.

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Now let's say I create a variable called a in a year.

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What's happening here now?

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Well, this variable A is actually a variable.

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A is a variable.

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And now here, this a

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is a parameter.

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Now, there are multiple things that we need to look at.

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One thing is that this variable A, as I said, is not the same as this parameter A.

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So what I can do is I can say for a is going to be a.

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So now this a here, our power meter, whatever value it has, will be passed to our variable called

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a, which is this variable here.

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And now we can go ahead and.

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Code printed, so a is and a now, which of the A's will now be printed?

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Will it be the perimeter?

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Or will it be the variable?

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Well, it will be the variable we can see it if we just assign a value of four here, for example.

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So I'm going to assign a value of four to my a variable.

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And if I run it, you will see that a is four, even though we past five as the eight to it.

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So there we are.

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It says a is four.

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So now you might wonder why Scotland allow us to declare variable with the same name as a parameter

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inside the method.

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Well, somebody else have the same question.

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And here's an answer that was considered correct.

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This is called shattering, and it is useful for decoupling your code from other parts of the system.

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It is possible because names are bound to the current scope.

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So here we see this key word scope again.

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Now you can, of course, pause the video and read through all of this, but I personally like to go

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to the recommendations directly, which is number one, your code becomes hard to read as two different

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things have the same name, which leads to confusion, which already happened.

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So I think it's already confusing what we have there.

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And another disadvantages once shut out, you can no longer access the original variable within a scope.

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So.

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If you look back here, we have no way of accessing this variable anymore, except for if we actually

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assign it to our VAR A. and then use it.

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But then we could have gotten rid of all this.

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The whole thing from the get go.

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So this would work already or even without this VAR a equals A..

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OK.

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So this is just one part of scope.

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Another part of scope is the fact that and I'm just going to create a different variable here.

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I'm going to call this one be.

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Our variable, be that we create here, we can use it easily within our function, right, because it's

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within scope.

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That's where it was created, so that's where we can use it.

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But we cannot use it outside of this function.

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So I cannot go ahead and say be is equal to three, for example.

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This doesn't work because it doesn't find to be unresolved.

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References what it says.

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OK, so if I create a local variable in here called be this variable D is going to be a very different

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variable than this variable B here.

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So they are all only visible within the scope of themselves, which is within the scope of their own

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function, or if it's within a class, then within the whole class.

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So if I create a variable B here and I want to use it in here.

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So let's say I want to assign variable B here and like this here, this is going to work because this

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variable is created outside of functions, so it's available within the same file.

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So in our case, within the same Scotland file, so it's available for our main function, but also

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for our my function function.

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OK.

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So this is the whole idea of scope, and I hope this will make things a lot clearer as we move on.