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OK, so moving on with classes here, you notice that I have the same class that we were discussing

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in the last lecture.

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I have it here in Visual Studio Code.

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So here is the class definition here, and this is our blueprint.

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You notice that we have the private member variables section and public member functions section.

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So let's see what's below that.

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Here we have something we also talked about in the last lecture, which is the actual implementations

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of the member functions.

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So remember the scope of resolution here.

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So this is the scope resolution operator and we are using the name of the class right before it, right?

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And then afterwards comes the name of the function.

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So this is kind of like one big name.

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Here we have the return type of each function is going to be coming before the car, colon, colon.

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And these are all of our functions that we discussed.

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So down below all these functions, I am putting my main function here.

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And so now what we're going to discuss is what to do when we're creating an object of the car class.

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So now we want to make a specific car, right?

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We have the blueprint up here and we have the function implementations, but now we need to make an

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actual car object.

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It's going to be just like how it made a structure.

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So I can say car capital C, right?

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Because that is what we named our class.

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In one of my call, this lower case, the car has the variable name so simple as that I make a car and

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then so let's try something interesting now I have a car, right?

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Well, let's go ahead and use some of these functions, right?

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Let's do get odometer and get fuel so I can do see see, our car is my variable right and then we're

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going to use a dot just like the struct in real.

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In the struct, we use a dot to access the members.

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Well, here I put a dot and you notice that it gives me the option to call any one of these functions

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here.

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So I have drive car, get fuel.

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Let's go ahead and get odometer.

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That's a function call.

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So I need to put some parentheses right here.

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You can think of this as like a string dot, dot string dot length or something like that.

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Another interesting thing to talk about is the fact that, you know, string.

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I'm using it as an example, but string actually is an object and it's actually a class.

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There's a string class.

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And when you're using that standard namespace, you know, it's kind of just par C++ in general.

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You can just use strings, you have access to that class.

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And so therefore you can use the member functions of that class.

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One of the member functions is length.

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So when we make a string like string s or something like that, we do escort length.

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It's similar to how we're doing car dot, get odometer.

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So I just want to point that out.

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That string is a class, so maybe that can kind of tie together some things that you've seen so far.

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So this kind of interesting let's see what would print out, I mean, we haven't really said what the

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odometer is when you make a new car, right?

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So I'm going to be interesting seeing what prints out.

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Put it in line.

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And then let's also see our car door get fuel.

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So this is going to return the fuel to us.

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And that's all I want to do.

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I'm just going to print these two out and that'll be the program.

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So I'm going, go ahead and save this.

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And then here I have a terminal.

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Go ahead and compile.

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And then I'm going to run this and let's see what we get as output.

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OK, so supposedly we have.

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For what is this four million, two hundred one thousand three hundred thirty nine miles on our new

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car?

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That doesn't seem very good, right?

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And then we have, you know, this crazy number right here as our fuel.

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So why do we have those numbers?

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Well, this is something that you might already know, but what's happening is that this is garbage.

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This is some of those garbage values.

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This is just coming out of memory.

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We've created these variables fuel and odometer, where we make those we define to them here.

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Was there float fuel in odometer?

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The problem is, is that we never initialized these variables.

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So when we make a car object, it basically when it tries to call get odometer, which it does, it

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doesn't try, it does call it odometer, it goes here, says return odometer.

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We get the value of the odometer back here.

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But what is the value of odometer?

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It's just some random trash from memory just picks up wherever that variable is sitting and memory is

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just going to pick up whatever's there.

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And that could be anything, you know, and it's just interpreting that garbage as these bytes as this

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decimal number here because of the data type, right?

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It's an integer du type.

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And then we have a float in that flow is just some crazy number two.

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So what do we do about that?

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How do we initialize these variables?

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So that is something we're going to talk about next.

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Now you see that we have created a car.

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And this is the syntax is similar to kind of a struct.

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But what if we wanted to say exactly what a car is going to start out with as far as the odometer and

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the fuel one odometer?

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We know what that should start out as it should start out as zero right, like zero miles for a new

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car.

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So what we can do is actually make something in the code up here.

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And this is something pretty interesting, kind of unique to classes, it is called a constructor.

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And the reason is called a constructor is because it is what gets called when you build the object.

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So constructing is kind of like build, the same thing is building, right?

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Those things are kind of synonymous.

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So here is where you create a car object right on this line right here.

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So you can think of this when you do this, it is going to call a special function called a constructor.

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And since we're calling it on this line here, you know, we wouldn't put like a dot right away for

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a function because we need to have this style syntax that creates the car variable, right?

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So we're not going to put a dot when C++ sees this, it's just going to automatically call our constructor.

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So the question now is how do we make a constructor and what is it?

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Well, it is going to be here in our public methods function or public member functions area, but it's

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going to look like this is just going to literally be the same name as the class with some parentheses.

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And so this is an empty default constructor, is what we call this.

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You're going to call the name is basically like a function like drive car, except the name of the function

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is the exact same as the class name, and you do not put a data type.

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There is no void.

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No in no float.

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Don't put that.

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Just put the name of the class with some parentheses here, and they don't have to be empty.

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We're going to get into that in a second.

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But right now, we're going to leave them empty.

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And so this is a basic default constructor, and you can put it here in the public number functions

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area.

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So I'm going to have to actually make an implementation of this, just like I did for these functions,

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so let's go down here and see what that's going to look like.

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I'm going to put it above all of these other functions in terms of top to bottom.

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And I'm going to go ahead and put this scope resolution just like this function car call and colon.

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So I can actually copy that and I can go over here and I can paste that so I don't have a car.

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And then I just put the same thing again, car, because that's the name, right?

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That's the name of the constructor.

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It's just car.

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It's the same as the class name looks kind of weird because we have Capital C car call and call colon

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and then just Capital C car coming right after it.

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But that's how it's supposed to be.

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Syntax was so I'm going to make it just like a function.

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I'm going to put some brackets here.

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And so this function is constructor is going to get called right here when we make the object.

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This is us making the car and so, you know, once we make the car, it's going to be like, Oh, you're

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making a car, I'm going to jump and up and try and find this constructor and then I'm going to run

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whatever code is in here.

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So what do we want to put in here?

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Well, the constructor is all about initializing our private variables.

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There's other stuff you can do in the constructor.

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I mean, technically, you can do whatever you want, but one of the main things that we're going to

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start doing is initializing these member variables that we're in this private section here.

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So what do we want for fuel?

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Well, fuel should probably start out as something other than zero.

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So I'm just going to say I don't know how many gallons, let's just say like 12 gallons or something

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like that.

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And then I'm going to say odometer equals zero because we're going to start out with no miles, right?

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And then we can just put some default paint color.

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We could say not string sorry and we could save paint color.

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Let's say that all of them kind of.

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Come off, you know, without really having paint, there's something, you know, maybe maybe the default

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color is just metal or something like that.

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We just say that and then model and we'll just say this is blank.

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Well, you don't have to put metal or something.

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We can just put a blank string here for Painkiller as well.

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So that way, at least there is something there for the painkiller model, even though it doesn't really

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have any meaning, it's just an empty string.

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Quite often in the constructor, you'll find yourself initializing these member variables to like the

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most basic value you can think of, so integers will often be zero.

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But this is actually a float like that, so let's put a four, 12, 12 point zero.

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And we got to put semicolons here, right?

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So.

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A lot of the things that you're going to see in here are going to be basic values, so like we're saying

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12 for fuel, just because it doesn't make sense to really start out with a car having no fuel when

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you want to drive it off the lot, right?

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But a lot of times floats will be zero point zero.

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Integers will be zero.

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Strings will be empty.

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String so on and so forth.

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But they don't always have to be.

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I'm just saying that that's kind of a common thing if you don't really have a specific value in mind

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first, just to initialize it to the most basic thing possible.

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So we're initialized in all four of our member variables here.

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So let's go ahead and save this and recompile it now and see what happens.

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So notice I've prototyped it up here, implementations right here and then down here we are still instantiating

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our car.

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So just another reminder on that when we make an object of a certain class, it's called instantiating

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it.

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We make an instance of the car class, right?

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So let's go ahead and test this out and see what happens.

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So I'm going to go ahead and save this, and then we're going to go down here and we compile it and

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then run.

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All right, so what do we see now?

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Well, the get odometer returned to zero because we have zero miles in the jet fuel is 12 gallons.

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So this is what we start off with now.

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The basic car, so you notice that these values get odometer is just getting the odometer and get fuel

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is just getting the fuel.

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And why are they zero in 12?

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Well, because when we created the car and where do we create the car right here on Line 50, right?

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When we created the car, what it did was they called this constructor code right here and it set fuel

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to $12 zero in the painkillers in model here to empty string.

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So that is a default constructor.

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This is when we have no arguments being passed to it, we have no parameters that we've defined.

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The thing is is that if we want to, we can say when we make a car, how many miles we want on the car

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and how much fuel we want in the tank and what color car we want and what model car we want.

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And that's kind of normal, right?

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Maybe not how much fuel is in it, but it's normal to say, OK, well, I want a used car that has,

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you know, about 50 thousand miles and I want the color to be white and I want the model to be this,

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you know?

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So that's something pretty normal, so why don't we implement a constructor that can handle stuff from

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the user?

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00:14:07,930 --> 00:14:15,730
It can have a base line car that has the parameters that the user describes if the user can pass those

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as arguments.

197
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So I'm going to add one more thing here.

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Instead of just model, I'm actually going to say I'm going to have an extra thing here, and I'm just

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00:14:25,300 --> 00:14:26,780
going to call this like a.

200
00:14:28,360 --> 00:14:30,490
A strange branch, I call it.

201
00:14:31,540 --> 00:14:34,570
Yeah, I guess I'll just call this like the brand of car.

202
00:14:37,660 --> 00:14:41,770
And then I'm not going to have a brand or any of that stuff.

203
00:14:42,340 --> 00:14:46,150
So what are we going to do if we want the user to say this?

204
00:14:46,150 --> 00:14:51,880
So let's go ahead and have the user choose not the.

205
00:14:53,060 --> 00:14:57,740
Fuel, because that would just be up to where, you know, the dealership or whatever, but let's say

206
00:14:57,740 --> 00:15:03,290
paint, color, brand model and odometer, so we're going to have three strings.

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00:15:03,300 --> 00:15:17,810
And so let's just say the string paint a steady string and we'll just call this.

208
00:15:18,170 --> 00:15:19,370
This is the brand.

209
00:15:23,090 --> 00:15:31,800
Let me just call this brand and then I'll say a Stevie string model.

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00:15:32,270 --> 00:15:38,300
And then and then the last parameter here will be ends in this will be miles.

211
00:15:41,070 --> 00:15:45,060
So we'll see how many miles they want in the car, and we'll say all this stuff, so we notice that

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00:15:45,060 --> 00:15:51,900
we have a similar named parameters here to this stuff here like brand and model.

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00:15:52,890 --> 00:15:58,140
So what I'm actually going to do and this is just something that I like to do quite often, is I like

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00:15:58,140 --> 00:15:59,850
to put a little underscore in front of these.

215
00:16:00,180 --> 00:16:04,410
So I'm actually going to name these with a little underscore.

216
00:16:07,950 --> 00:16:09,840
And this is something this is not just me.

217
00:16:10,260 --> 00:16:15,630
A lot of people like to name their member variables like this actually applies to some other programming

218
00:16:15,630 --> 00:16:16,470
languages as well.

219
00:16:17,640 --> 00:16:22,440
So what we're going to have to do then is put underscores one of returning these things, and I'm going

220
00:16:22,440 --> 00:16:23,340
to have to update this.

221
00:16:23,340 --> 00:16:25,260
So it's going to underscore Odometer.

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00:16:28,790 --> 00:16:34,880
And then this, of course, will be these I can handle them because I'm going to change that.

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00:16:35,270 --> 00:16:37,220
And let's see Painkiller.

224
00:16:39,790 --> 00:16:40,540
Phil?

225
00:16:42,930 --> 00:16:43,210
Deal.

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00:16:43,650 --> 00:16:45,230
All right, cool.

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So I have changed these now, and I'll fix those in a second.

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So we have these parameters now and we're putting this is remember, this is our prototype here, so

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we have to define the parameters in the prototype as well for the constructor.

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And of course, all these other functions.

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So let's go down here and handle the implementation.

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So.

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We're going to copy and paste all of this in here, so I'm going to go ahead and copy this.

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Let's go ahead and put it here in our implementation.

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The parameters?

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00:17:17,070 --> 00:17:20,640
And so what I'm going to do, remember our field stays the same with the rest of these are going to

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get set to these things that get passed now as arguments to the constructor.

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00:17:27,210 --> 00:17:30,210
So what I'm going to do is I'm actually going to

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leave feel the same, but I'll say odometer equals miles.

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And then paint color.

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Going to be able to paint that the user's passing model is going to be equal to the model that these

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are passing.

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00:17:48,340 --> 00:17:53,530
And let's go ahead and also put the brand here and we'll say brand equals brand.

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Cool, so now the user can kind of specify what type of car they want to start out with.

245
00:18:03,140 --> 00:18:04,770
So let's go ahead and check this out.

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00:18:04,790 --> 00:18:06,680
Let's see how we're going to do it in the code down here.

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00:18:06,680 --> 00:18:14,020
So what we can do is now we just have this car was like this without any parentheses, right?

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Even though that was kind of a function we were calling for, the constructor is still worked without

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frenzied, but now we're going to put parentheses because we want to specify the arguments for our car.

250
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So let's see patent brand motto miles.

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00:18:28,740 --> 00:18:35,210
So let's say we want the paint color to just be like blue.

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We want the brand to be like, I'm just going to say something like silver.

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I like serious.

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00:18:43,130 --> 00:18:52,470
And then let's say the model will be something like the X or something like that or.

255
00:18:52,610 --> 00:18:57,230
Yeah, and Impreza or something crazy not to spell that.

256
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Others say outback or something like that.

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And then we have.

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00:19:04,560 --> 00:19:10,770
The was it Miles, right, and so we want to use car and we say, well, we just want something like,

259
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you know, forty thousand miles or something like that.

260
00:19:16,110 --> 00:19:18,270
So let's go ahead and try this out now.

261
00:19:18,270 --> 00:19:19,200
So now we have.

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00:19:20,980 --> 00:19:22,330
All right, get odometer.

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00:19:23,110 --> 00:19:31,630
And we have our jet fuel, let's as some other stuff, so let's say see out car dot and now see we we

264
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need some more accessories.

265
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So let's see.

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We have the.

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00:19:41,220 --> 00:19:47,940
Painting toilets out of some a couple more minutes in here, so we can test out our our color and brand

268
00:19:47,940 --> 00:19:50,040
and stuff, so let's see.

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Steady string and we will say get.

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Get paint us give.

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00:20:04,200 --> 00:20:05,010
Get paint.

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And now, let's say a steady string, and I get brand as steady string and get model.

273
00:20:21,360 --> 00:20:24,960
And yeah, that should do that should do for us.

274
00:20:25,110 --> 00:20:28,880
We also have this set paint here, so let's go ahead and test it out as well.

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00:20:28,890 --> 00:20:31,290
So these are going to need to be implemented now.

276
00:20:31,680 --> 00:20:34,260
So we have this get paint, get brand, get model.

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So I'm going to go down here.

278
00:20:37,340 --> 00:20:46,520
Well, let's do it after sit paint, so we will say as TV's string car and colon get paint.

279
00:20:47,270 --> 00:20:51,530
And so this should just return a paint color.

280
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Oops.

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00:20:56,420 --> 00:20:58,370
Let's go ahead and do that in the other ones.

282
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So this one will be get model.

283
00:21:03,170 --> 00:21:06,890
And so I will just say return model.

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And then let's say a steady string car gets brand and we will go ahead and just return France here as

285
00:21:21,500 --> 00:21:21,830
well.

286
00:21:21,860 --> 00:21:23,450
And I believe that was all three.

287
00:21:23,840 --> 00:21:24,590
Right, so.

288
00:21:25,770 --> 00:21:28,110
We have let's go check our function here.

289
00:21:28,140 --> 00:21:30,630
So get paint, get behind your model, those are the new ones.

290
00:21:32,420 --> 00:21:41,720
All right, so let's go ahead and test out here then, so we'll say see out card, get paint.

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00:21:44,810 --> 00:21:50,870
And then let's go ahead and do a function call right here where we say a car got set paint and now we

292
00:21:50,870 --> 00:21:57,590
change, let's say, like, Oh, I'm going to repaint my car unless paid in black, and then let's go

293
00:21:57,590 --> 00:22:04,250
ahead and do another Seattle card dot get paint right to show how that's changed.

294
00:22:08,350 --> 00:22:13,320
Right, because our get paid here are set paint, we take a string, right?

295
00:22:13,350 --> 00:22:18,030
So sipping here takes a string and then it says the paint color to that color.

296
00:22:18,040 --> 00:22:21,670
So if we can't get paint again, we won't have that new painkiller.

297
00:22:21,910 --> 00:22:24,340
This is a cool thing about classes.

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00:22:25,870 --> 00:22:32,440
These member variables are shared across the class, so.

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00:22:33,830 --> 00:22:39,470
We defined all of these member variables here, right in their private private means that down here

300
00:22:39,470 --> 00:22:44,150
in Maine, we don't really have, you know, an access to that.

301
00:22:44,420 --> 00:22:52,430
So but here when we put these functions here that aren't Maine, but they say car colon, colon, the

302
00:22:52,430 --> 00:22:56,710
car colon, colon is giving us access to the private data members.

303
00:22:56,720 --> 00:23:02,630
So the interesting thing is if we change paint color, it stays the same across this whole class.

304
00:23:02,630 --> 00:23:08,540
So when we call this method again, it's going to get the updated paint color right, so it saves the

305
00:23:08,540 --> 00:23:10,250
state of the paint color.

306
00:23:12,420 --> 00:23:14,770
So let's go ahead and prove this right.

307
00:23:14,850 --> 00:23:18,210
So let me go ahead and save it, and then I'm going to compile it.

308
00:23:18,930 --> 00:23:22,040
Let's run it and let's see how this works out.

309
00:23:22,050 --> 00:23:26,640
So what we do get odometer, it started out at 40000, right?

310
00:23:26,910 --> 00:23:30,180
So when we print this out, it shows 40000 wheels.

311
00:23:30,180 --> 00:23:32,370
The next thing we print out car to get fuel.

312
00:23:32,640 --> 00:23:35,550
We never set our fuel explicitly here.

313
00:23:35,790 --> 00:23:38,430
When we made the object right, that was not for the user.

314
00:23:38,640 --> 00:23:41,730
The default constructor set the fuel to twelve point zero.

315
00:23:42,180 --> 00:23:48,280
So we go ahead and we print that out and we have 12 here, and then we do a get paint well.

316
00:23:48,350 --> 00:23:51,090
The original paint that the user specified was blue.

317
00:23:51,240 --> 00:23:57,510
So when we call it Clinton, says blue, then we say car got set paint, which sets it to black.

318
00:23:57,810 --> 00:23:59,220
What happens with this?

319
00:23:59,910 --> 00:24:06,840
This gets this black right here in this function call it gets sent up here to set paint.

320
00:24:06,870 --> 00:24:08,160
So black is here.

321
00:24:08,160 --> 00:24:10,650
And then it says painkiller now equals black.

322
00:24:11,070 --> 00:24:15,300
The next thing we're doing is doing a C out of get paint, right?

323
00:24:15,750 --> 00:24:17,850
So we see our car get paid.

324
00:24:19,220 --> 00:24:23,660
Go up here and we do get paid paint Painkiller has been set to black.

325
00:24:23,930 --> 00:24:27,620
This state is saved across this whole class.

326
00:24:27,980 --> 00:24:29,960
This is considered as part of the class.

327
00:24:29,960 --> 00:24:33,680
Be here because as car coal and coal in scope resolution operator here.

328
00:24:34,250 --> 00:24:38,300
So that's why we see that it now prints black when we print it out down here.

329
00:24:40,750 --> 00:24:42,250
So pretty cool.

330
00:24:42,490 --> 00:24:51,310
Now we know not only how to make a constructor, but we also know how to pass arguments to it and initialize

331
00:24:51,310 --> 00:24:56,110
the values to the user's choice kind of where they pass these arguments.

332
00:24:57,760 --> 00:25:04,690
So another important thing that we've been doing is using these things called getters and setters,

333
00:25:04,690 --> 00:25:11,570
which would be get paint and set paint, get odometer, get fuel, get paint.

334
00:25:11,590 --> 00:25:20,410
So these are getters when it says get and you also can refer to getters and setters as accessories and

335
00:25:20,770 --> 00:25:21,340
haters.

336
00:25:21,730 --> 00:25:28,420
So a getter is also an accessory, and a setter is also a mutate or mutate.

337
00:25:28,420 --> 00:25:33,130
Or just mean to change a setter is something that changes the color, right?

338
00:25:33,490 --> 00:25:38,950
So we have set paint changes the color to black, but get paid just gets you.

339
00:25:38,950 --> 00:25:42,160
Whatever the current state of paint, color is right.

340
00:25:42,160 --> 00:25:48,400
We have paint color here and whatever the current state of paint color is, when we call get paint,

341
00:25:48,400 --> 00:25:51,850
all it doesn't just return you whatever value is currently stored in there.

342
00:25:52,750 --> 00:26:00,200
This access, this mutate or here or this center is to change is for change it, for modifying.

343
00:26:00,200 --> 00:26:05,650
It makes a modification to this variable right and it makes the modification based on whatever color

344
00:26:05,650 --> 00:26:09,020
gets passed as an argument because you see this parameter here.

345
00:26:10,510 --> 00:26:13,360
So it's pretty cool.

346
00:26:14,020 --> 00:26:19,380
Another cool thing is that we're not limited to making one car, we can make as many cars as we want,

347
00:26:19,390 --> 00:26:20,950
so let's go ahead and make another car.

348
00:26:21,160 --> 00:26:27,550
I'm actually going to just call this car to car car two, and I'm going to say this one was white and

349
00:26:27,550 --> 00:26:29,200
this is a Ford.

350
00:26:29,560 --> 00:26:30,850
And it is.

351
00:26:32,170 --> 00:26:32,860
Let's see.

352
00:26:33,220 --> 00:26:37,930
The model is like a Ford Fiesta.

353
00:26:38,320 --> 00:26:42,550
And then we have the miles are only ten thousand.

354
00:26:43,060 --> 00:26:43,690
How about that?

355
00:26:44,410 --> 00:26:48,580
So let's go ahead and print these separate things out.

356
00:26:48,580 --> 00:26:56,860
So what we can do is we could see out and we can say, let's say car one.

357
00:26:58,480 --> 00:27:02,290
Uh, let's say car one miles.

358
00:27:04,930 --> 00:27:08,170
And we'll say car get odometer.

359
00:27:11,540 --> 00:27:15,230
And now we can actually say a car to.

360
00:27:19,860 --> 00:27:21,000
Let me just do this.

361
00:27:21,520 --> 00:27:24,360
I'm sorry for the struggle at the time, this kind of real right now.

362
00:27:25,980 --> 00:27:43,500
So we say car two miles and here I can put up this year and then we can say car two dogs get odometer

363
00:27:44,000 --> 00:27:44,200
right?

364
00:27:46,590 --> 00:27:52,740
So this will put ice probably for a space after this, so let's actually put a couple of spaces there.

365
00:27:55,680 --> 00:27:56,590
Yeah, there we go.

366
00:27:56,620 --> 00:28:03,030
And so we'll have the car, one miles will for now and we're doing car to get odometer right and then

367
00:28:03,030 --> 00:28:10,650
the second one would do a cartoon odometer and it will show us the values, default values of the second

368
00:28:10,650 --> 00:28:12,920
car so we can make as many objects as we want.

369
00:28:12,930 --> 00:28:15,120
Let's go ahead and just print this out to see what it looks like.

370
00:28:18,840 --> 00:28:19,350
All right.

371
00:28:19,890 --> 00:28:25,870
So we see a car one starts out with 40000 miles as expected and car to start out with 10000 miles,

372
00:28:25,870 --> 00:28:27,870
so you notice that we initialized it here.

373
00:28:28,380 --> 00:28:31,770
It knows which object has which data, right?

374
00:28:31,770 --> 00:28:37,710
We explicitly said Car two is an object that has this data that is held somewhere in memory.

375
00:28:38,130 --> 00:28:45,720
This object, when we refer to get odometer of car to it, is different, then referring to get odometer

376
00:28:45,720 --> 00:28:48,660
of the original car object that we made.

377
00:28:49,140 --> 00:28:49,430
Right.

378
00:28:49,440 --> 00:28:55,890
So you can make different objects now, and they can, of course, have different data associated with

379
00:28:55,890 --> 00:28:56,250
them, right?

380
00:28:56,270 --> 00:28:59,250
One is a Ford Fiesta with 10000 miles.

381
00:28:59,250 --> 00:29:01,440
The other one is a blue Subaru Outback.

382
00:29:01,440 --> 00:29:04,530
That's 40000 miles that later gets painted to black.

383
00:29:06,320 --> 00:29:10,680
OK, so I think I'm going to stop here for this lesson, I'm not trying to overload too much.

384
00:29:10,700 --> 00:29:14,050
We have a lot to go over with objects and classes.

385
00:29:14,060 --> 00:29:17,390
There's just a ton of stuff you can do with object oriented programming.

386
00:29:17,930 --> 00:29:23,120
Right now, the focus is just trying to get you comfortable with making classes.

387
00:29:23,420 --> 00:29:30,380
So making the blueprint, understanding what public and private are the difference between them being

388
00:29:30,380 --> 00:29:35,690
able to implement all of the prototypes that you put it here in the blueprint and the implementation

389
00:29:35,690 --> 00:29:36,420
goes here?

390
00:29:36,950 --> 00:29:37,250
Right?

391
00:29:37,280 --> 00:29:40,430
These are all the implementations understanding you have to use this.

392
00:29:41,030 --> 00:29:44,240
The class name Colin Colin before the member functions.

393
00:29:45,560 --> 00:29:50,810
And then, of course, now after this lecture, I expect you to understand what a constructor is, how

394
00:29:50,810 --> 00:29:59,630
to declare a constructor here in the public function section and how to implement a constructor here

395
00:29:59,630 --> 00:30:06,740
down past the class blueprint where and also not only know how to do it with empty parentheses here,

396
00:30:06,740 --> 00:30:11,630
but have parameters and know how to initialize all of your member variables.

397
00:30:11,630 --> 00:30:18,950
The private number of variables to either the parameters that have arguments being passed or just initialize

398
00:30:18,950 --> 00:30:24,710
them like feel here to some default value that was decided by you as the software engineer.

399
00:30:26,390 --> 00:30:31,850
Also, of course, knowing how to instantiate everything and knowing how to call methods on it, you

400
00:30:31,850 --> 00:30:34,790
know, it's just like string se length.

401
00:30:35,360 --> 00:30:39,830
Remember, like I said, string is a class just like car.

402
00:30:40,220 --> 00:30:47,090
Somebody else made class in this word right here was string and they had all kinds of functions.

403
00:30:47,330 --> 00:30:50,390
One of these functions is what is a length.

404
00:30:50,870 --> 00:30:52,430
So the name of it is length.

405
00:30:52,940 --> 00:30:56,840
And they made an implementation that said, String Colin, call in length, you know, and it's going

406
00:30:56,840 --> 00:31:00,740
to tell you how it's going to give you back the length of the string.

407
00:31:02,280 --> 00:31:03,990
So pretty cool, right?

408
00:31:04,920 --> 00:31:09,330
So with that, I think I'm going to stop here and I will see you in the next lesson where we continue

409
00:31:09,330 --> 00:31:13,680
on with more of these object oriented programming practices and concepts.