1

00:00:00,490 --> 00:00:02,770

So how did you find that fairly easy?



2

00:00:03,070 --> 00:00:06,610

I'm guessing the hard part was figuring out what variables you were going to use.



3

00:00:07,180 --> 00:00:08,170

Well, here's my version.



4

00:00:08,420 --> 00:00:11,350

A class of gadget has keyboard, has SIM card.



5

00:00:12,680 --> 00:00:19,050

So gadget's usually don't have a SIM card and gadgets usually do have a keyboard.



6

00:00:19,700 --> 00:00:22,790

How would we subclass that to define a smartphone?



7

00:00:23,420 --> 00:00:23,780

Well.



8

00:00:25,760 --> 00:00:30,800

We would say smartphone inherits from gadget and we're going to override its initial.



9

00:00:31,340 --> 00:00:37,580

So even though we haven't specified the initialise here, here, we're still going to override it.



10

00:00:37,610 --> 00:00:38,600

We're going to call super.



11

00:00:38,610 --> 00:00:42,800

So it's still initializes everything because look what happens if we leave this out.



12

00:00:44,240 --> 00:00:47,570

Give it a second to catch up, we get Megaera.



13

00:00:49,840 --> 00:00:54,610

And then after it's done what it does, we then set keyboard to false because smartphones don't really



14

00:00:54,610 --> 00:01:00,530

these days or physical keyboard and self-taught has SIM card equal to true.



15

00:01:01,180 --> 00:01:07,690

And then, of course, if we're going to print that out, we could say smartphone object dot.



16

00:01:08,790 --> 00:01:09,480

Has keyboard.



17

00:01:11,310 --> 00:01:12,690

And that will say false.



18

00:01:14,160 --> 00:01:20,850

OK, now it's important to note that and I I should have mentioned this before smartphone.



19

00:01:22,750 --> 00:01:23,620

Smartphone.



20

00:01:24,950 --> 00:01:34,040

Are all different objects, so if I change keyboard on this one, it has absolutely no effect on this



21

00:01:34,040 --> 00:01:35,090

one or this one.



22

00:01:36,050 --> 00:01:42,650

Every object has its own copy of the variables and the functionality inside of it, so they each have



23

00:01:42,650 --> 00:01:49,520

their own state, right state represents what the data looks like at any one point in time inside the



24

00:01:49,520 --> 00:01:49,910

object.



25

00:01:51,440 --> 00:01:55,940

So I should have really mentioned that, and it doesn't matter how many times you create it, the state



26

00:01:55,940 --> 00:01:56,690

is always the same.



27

00:01:57,500 --> 00:02:01,800

The state is always inside, contained inside of that object.



28

00:02:02,600 --> 00:02:05,960

Now, some languages allow you to use what are called static variables.



29

00:02:07,880 --> 00:02:10,580

I would say avoid static variables like the plague.



30

00:02:10,590 --> 00:02:16,730

So if we're in a smartphone, if you're in C sharp, you'd have a static var.



31

00:02:19,790 --> 00:02:21,060

What else is on a smartphone?



32

00:02:21,080 --> 00:02:21,500

I don't know.



33

00:02:22,960 --> 00:02:24,340

Battery equals true.



34

00:02:26,420 --> 00:02:29,600

OK, now it's just going to work on this.



35

00:02:30,550 --> 00:02:38,350

Apparently, it was just a random guess that in that case for this this is going to be the same for



36

00:02:38,350 --> 00:02:40,090

all of these bright.



37

00:02:41,190 --> 00:02:47,880

Even if you try to change it, but if I try and take a battery, I can't access it.



38

00:02:49,090 --> 00:02:49,800

Why is that?



39

00:02:50,140 --> 00:02:57,400

Because it has nothing to do with the object or instance we created, it has to do with the original



40

00:02:58,330 --> 00:03:05,920

class so I can access it if I don't put the brackets here to make it into an object.



41

00:03:06,190 --> 00:03:08,680

And I'm just looking at the class.



42

00:03:09,670 --> 00:03:11,200

OK, so that's how that works.



43

00:03:11,740 --> 00:03:16,630

Avoid static's really, really, really, really avoid static's if you can.



44

00:03:16,810 --> 00:03:23,320

Again, some situations where you have to use them or put my hand up and admit this, you're being lazy,



45

00:03:23,470 --> 00:03:29,410

you just throw in a static here and there, but for the most part and please, please avoid them.



46

00:03:29,860 --> 00:03:30,210

All right.



47

00:03:30,550 --> 00:03:32,140

That's inheritance done.