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Now, let's look at two more concepts nested class and in a class, and we are going to need them later

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on.

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So let's look at the concepts here, a class which is created inside another class and a class which

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is created inside another class with the key word inner.

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So this is the difference between the two.

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But there are a little more differences that we need to look at.

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So let's look at the master class first in the class.

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Such a class which is created inside another class in another class is by default static so its data

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members and member functions can be accessed without creating an object of the class.

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So without having to create an object of this nesto class, you can go ahead and use the functions and

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members.

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Then the class cannot access the data.

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Members of the outer class.

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So it's a one way relationship.

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So only the upper class can access the members of the master class, but not the other way around.

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So let's look at this.

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We have a class called our class and then inside of this class we create another class called Master

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Class.

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OK, and usually you should create classes which are separated so each having their own file, but sometimes

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it just makes sense to have an asset class.

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For example, if you really just need its functionality within the hour class that we're using here,

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and this is classic example that we see here, is that we have this upper class and there we have a

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variable called name and it said to Mr X and then we have this class which has a description and then

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it has an ID, which is of type int at a function called Foo, which just prints the name and the ID,

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and then we go to our main function where we try to access the description.

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So in order to access the description, we go to our outer class and then inside of that we go to the

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next class.

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So we're accessing the property here and then we create an object of the class and we access the function.

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So the function of that master class, so the output is code inside the NSA class and it is one on one.

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So now let's look at the inner class concept.

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And in a class is a class which is created inside another class with the key word inner.

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In other words, we can say that the NSA class, which is marked as inner, is called an inner class.

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So it's still an asset class, but it has this additional keyword.

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Right.

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But the difference now is an upper class cannot be declared inside interfaces or noninsured asset classes.

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And the advantage of inner classes is that they are able to access members of its outer class even though

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they are private.

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So this is the huge difference, right.

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So the inner class keeps a reference to an object of its our class.

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So if we look at this example here, this is the syntax of an inner class.

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So we have the upper class and we have this master class, but we add the inner key word so inner just

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before the class keyboard.

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All right.

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And then if we look at this example that we had before, the only difference now is that we add in a

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key word here to our inner class and that we now can access name and ID.

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We could, of course, beforehand access the ID anyways, but we couldn't access the name.

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So you can see here the name that we're using is from the outer class.

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So here where we have this private key word, even so we say, OK, this is private.

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So it should only be available within this class.

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But with the inner classes, you actually have access to even private class members of the outer class.

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OK, so that's the huge difference in another class without this inner key word.

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This wouldn't be possible.

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So sometimes it just makes sense.

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And sometimes you just need this functionality and then you make it in a class and you can use it.

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So going back to our function name here we have our outer class inner class description so we can access

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the property as we did before, and we can also access the object fool.

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So we create an object of the inner class which is inside of our outer class, and then we can go ahead

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and use its member functions.

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So the output here is code inside in a class name is Mr X and it is one on one.

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So we didn't have this name is Mr X before.

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All right, so that's it for now, let's get back to where we are actually going to use this functionality

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and then we'll make a lot more sense because it's a little bit abstract to look at it that way.

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So let's get it into coding.