>> We're learning about C Sharp 101. I think we've reached
your favorite part. >> We have. Object
oriented programming. >> There it is. >> Yeah. This is the time in your C Sharp curriculum where
you know you've made it. Now we get into the
serious bits of C Sharp. We're going to go over inheritance, we're going go over objects.
It's going to be great. >> Awesome, cool. So what
I want to do is I've got my exploring object oriented programming documentation
up and I'm going to again, snap that off to one side. We just finished our
Fibonacci sequence. You could go and check
that video if you want to. But I think we should
just start from scratch. It's file new project time
right now; don't you think? >> Let's do it, yeah. >> Okay. So in Visual Studio, I'm going to say File, New, Project and we're going
to basically get rid of the previous one and start from
scratch with another console apps. So I'm going to get
ConsoleApp and we'll call it MySuperBank. All right. We're going to make a new
bank, and we'll hit Create, and then it's going to ask us if
we want to save our old project. I don't care about that old
project. We're going to toss that. We're starting from
scratch and we're back at Hello World and the only
thing that's changed, that it's MySuperBank
which is awesome. >> Better than other banks. >> It's way better. Other banks suck. Our
bank is the best bank. So what we want to do is think about object-oriented programming
and make a bank account. Now what is object-oriented program? What are objects and why are
we orienting around them? >> So objects are
basically a way that all computer languages can learn
how to mimic the real world. So in the real world, we organize a lot of information
in various different ways. With object-oriented
programming, we can say, "Hey, a person can have a name, and an address, and a hair
color, and that kind of thing." So people can have different
properties and it's just a way of grouping
all information. >> Right. I mean, we're
orienting around objects. Like I can make a mouse
object or a bank object. Then when you talk about inheritance, we can have animals and
there are types of animals. >> Yeah. >> You can have a hierarchy
just like you have in reality. >> Yeah, definitely. >> So it's intended I
think to be intuitive. So hopefully, you won't
find this too intimidating. Okay? So according to this tutorial, they want us to make a bank account. So then presumably, we need a bank account and it has
certain requirements. What is this list of requirements? >> Right. So it looks like we need a 10-digit number that will
uniquely identify the bank account. So this is one of the properties
that will be in our bank account. It need this string for the
name or the name of its owners. It needs a balance. It needs to be able to accept deposits
and withdrawals. So these are I guess capabilities
that'll be able to have, so they're not like a
single unit of data. It's actually like a function
that will be attached to that. >> That's a good point.
These first three are really characteristics or properties. >> Right. >> These seem like methods or things that it can do verbs and
then what are these two? These are kind of like rules. >> Yeah. So it looks like the initial not balanced must be positive. So I guess when we're
creating not balanced number, we need to make sure
that it's above zero and withdrawals can not
result in a negative balance, which makes a lot of sense. That would not be a good bank system. >> This is very typical of
object-orientation, right? There's going to be some
properties like things, cars have color and
banks have balances. Then there are the stuff they can do. Cars can drive, banks
can take deposits, and then there's
rules that like well, you're doing those things, don't exceed this speed, don't crash the car. >> Yeah. >> So we need to go
and start thinking about our bank account type. >> Yeah. >> Okay. >> So a lots of things
that sort of describe the behavior and the design of
what this object will look like. >> Now so far, we've been putting
everything in program.cs. I feel like bank account maybe
should go on another file? >> Yeah. Let's make a
bank account class. >> On the right-hand side
of Visual Studio here, there are these little fly out
tabs and when you click on them, different things fly out. Like I can go to GitHub or whatnot. I'm going to click on
Solution Explorer and push this little pin and this is going to let me see the
files inside of my program. I have one called
program.cs and in fact, I can open it up and see my Main. >> Oh yeah. >> So that's actually
not a file, is it? >> Yeah. >> That's showing me the
structure of my program. >> Yeah. So to list out
the classes that you have within that file as well as the
methods in each of those classes. >> So I'm want to right click using the right mouse
button and say, "Add". I could say New Item
and get a whole list of item or I can say Add Class. >> Let's do that one. >> All right. >> Add a class. >> Let's do Add class. So I
need to add bank account. This might be scary but
this is just a list all the great stuff that
you can add in the future. >> We're just going to
say, "Add Bank Account." That seems like a fair
thing to do and you look, it went into another file and it has the same
namespace, that same bucket. >> Right. >> All right. So look at this. We could copy paste or I could type in public because it's
available to the public, string number and
numbers only gettable. This is called a property. I can get numbers but I can't. Like once it's been assigned, I can't set the number. >> Right. >> But I don't want to keep
typing that. That's tedious. >> Okay. >> That's tedious.
I'm going to do this. Remember how before we typed
a [inaudible] and hit Tab? >> Uh-huh. >> Check this out. Prop tab, tab. >> A code snippet. >> Code snippets. Tab, tab. >> Okay. >> Owner, enter, enter. Prop, tab, tab. Decimal, tab, tab. Balance, enter, enter. Look at that. >> Man. >> That great. >> You could type it
the old fashioned way. >> No. Nonsense. I want the
computer to do the work. >> Tab, tab is your friend. >> Tab is great thing to remember. Anytime you're in Visual Studio, tabbing will probably
get you something, in worse case scenario,
it gets you whitespace. >> Right. >> Then let's grab
these two functions and then maybe you
can talk about those. >> So these were sort of the actions that were listed out
in their requirements. So it needed to accept deposits
and make withdrawals as well. So instead of properties, these are going to be methods. >> Sure. >> Everything that you
see in this class, these properties and these methods, all of these are members that
are just one part of this class. >> Right. When we made them all
public, public, public, public, that means that other
applications and other classes within our application can look at those and talk to those. >> Yeah. > If they were private, they would basically be secret just to bank account and no one
else would know about them. >> So right now your class
doesn't have public in front of it and we could also
change that accessibility level. >> That's a very good point. Then you should look
on the right here. You're going to get used to
seeing these symbols as you move through Visual
Studio and C Sharp. The number, and the
owner, and a balance, you can see their types
and their names and that's a nice view of what's going on. >> Yeah. >> All right. Let's go back over
here and see what's going on. We've got our members, and our
properties, and our methods. To open a new account,
we need to make one. We need to construct a bank account. >> Right. So far, we've designed what a
bank account should look like in different
properties it should have. But we haven't actually made one. >> Right. So if someone were
going to make a bank account, they would have to go and say, "Bank Account, it's
called a constructor." Now I could make a constructor
that doesn't really do anything, but you can't open a bank
account with nothing. >> Yeah. Like you at
least need a number. That's one of the requirements. >> You need a name, you
need an amount. Exactly. >> Since the number
doesn't have a setter, we should probably create it
at the constructor alarm. >> Yeah. So then let me think here. We've got what? We have
the name of the person. >> Yeah, that'll be one
of the input things. >> Okay. Then we were
doing datatypes before integers and logs, decimals. What is the right number
for a bank account? I mean, I have pennies
but I also have fractions of pennies.
It's not an inch. >> Interesting. So we declared the number up at the top
is this string, right? >> No. That's a great point actually. This number is the
bank account number, which might have letters in it. So it's actually a string but
the balance is a decimal. So why don't we make
the initial balance? >> That's right. >> A decimal as well. >> Because you need to have cents. >> Yes. >> So it needs to have
two decimal places. >> You have to have cents or whatever your fraction on currency is. >> Right. >> Okay. So here's where
it gets interesting. Those are arguments. How do I get those
into these properties? I basically needed to tell
it about this object that I'm in this object, the
one that I'm working on. >> Right. So the perimeters
are being input into the constructor but nothing's
actually been assigned. >> Right. This is where I think object-oriented programming gets
confusing to people because this is a description of
what a bank account could be like but it isn't a bank account. It's like a template for a bank account or a
description of a bank account. >> Or like a form
like we will require all of these things but we
haven't filled out the form yet. >> It is a form that we're filling out. That's a
great way to look at it. >> So these are the form fields and I need to make sure that this
information in the constructor when I make the form for
the first time goes into the form fields of whatever this
current account that we're on is. >> Yeah. >> So I'll say this. The owner of this account will be
the name that we just passed in and then this balance
will be the initial balance. After I've done that, that goes away and it's thrown away
because I copied it into here. Does that makes sense? >> Yeah. >> But look at this. It says you
don't even need to say this. I like to save this because it
means this object not that object. >>> Okay. >> But they're saying it
doesn't really matter. It's kind of like var. It's one of those things where
if you like the way it looks, use it and if you
don't, that's cool too. >> Cool. >> Okay. That's not the awesomeness Bank Account but at least I could make it and test it. So how would we do that? What would be the Bank
Account Hello World? >> Yeah. How do we call this? So now that we have an object, when we have the template
for it and everything, we need to actually input data. So let's call this, how about in our program? >> So back over in Hello World. >>.cs. Yeah. We can initialize. Remember, Main is like the main
entry point for any application. So when we run this application, we'll just create one bank
account. That's the goal. >> Okay. So var account equals and then we knew something and we'd never done
this before, have we? >> No, we haven't. >> Because we have always
been saying like zero. >> Yeah, something like that. >>> We've never knew something. Some people call it
like newing it up. Like as if newing is a verb. >> Interesting. >> Yeah, you've ever heard
that? You new up something? >> New it up. >> So let's new up a bank account
and then when we pass in, we'll say Kendra's
money and look at that. It actually gave you
the shape of that. It gave you the help
and if I had comma. >> Yeah, because we're calling
the constructor right now. >> Yeah, look. >> That we just defined as needing the parameters of a
string and the decimal. >>> Right. That's why
you use a Visual Studio. If I use Notepad, I
could do this but I wouldn't get all of this help. >> The hints. >> I wouldn't get all the
spell-checking, right? >> Yeah. So Kendra has a $1000. >> Maybe just add a few
zeros to that [inaudible] >> Congratulations, $10,000. >> Excellent. >> Very nicely done. Then Let's do a Console.WriteLine
just like before. So this Hello World
would be different. This is the Hello Bank
Account world, isn't it? >> Right. So let's go
into our string and I'm going to put that string
interpolation thing there, that's important. >> Yeah. >> So we'll say Account
and then something was created for Kendra with some money. Okay. So let's go and dig our
information out of our object there. So what does it account., see how I didn't get my IntelliSense
unless I spelled it right? >> Right. >> So account number was created for account owner with account balance. That's cool. Does that look like
a decent banking Hello World? >> Yeah, I think we can call that. >> All right. Let's give
that a try and see what happens. Look at that. >> Account blank. >> Account blank was created
for Kendra with $10,000. So when the next video, we're going to figure out what
a good account number would be, how to make one because
we're going to have lots of different accounts and we never even figured that part out. We only did my names and balances. >> Right. >> So that's just us defining
an object and making an object.
