Getting Started – Lecture 3 – C++ Language for Beginners

Learn C++ Language
Lecture # 03 – Getting Started

Learn C++ Language

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So if you open
up code blocks you’re going to want to click on Create a new project and then
click on
console application on mine it’s in the top right corner of the
window on yours it may be different but you want to click on console
application and then hit go then on the next window you want to hit next
until you get here.
Make sure you highlight C++ click Next again and then give your
project a name and man I’m just going
to call it Tauriel wind and then
specify a folder to keep it in.
Make sure it’s a folder that you can
find easily and then click next. Leave all the default settings on this
window right here. These are simply directory and compiler settings.
Just hit thinnish and then your project is created.
So right now you don’t see anything but if you go over here to the
left and click on sources you’ll
see the main does the file which stands
for main dot C plus plus.
And if you double click it you’ll see the code.
Now before we analyze this code I want to go ahead and show you how to run it
and what this code does and to do that on Windows you can either hit F 9
or if you’re on a Mac or Linux machine you can just go up here and hit
build and build and run.
The code will compile and then you’ll see this console window.
It prints the word hello world and then says Process returned 0.
OK so you can close up of this.
Now that we know what the code does is we’re gonna look at how this
code is what it is.
So beginning with kind of the main thing I want to
show you in this tutorial other than you know how
to run your first
program and compile it is you know how to type out the skeleton of a C++
It’s what I call the skeleton and it’s everything that you need for
your code to run at least in this
course any ways for every program that
we will be writing together.
So if we go ahead I want to go ahead and take out this line because
this line is not actually needed
for this program to compile and run.
So if we take it out and we hit F 9 and we build and run it again
we will get the processor turned to
We just won’t have
hello world printed to the console which means I mean that’s fine.
The program just ran and executed till it finished with no errors.
And it’s a perfectly good program. So if we exit out of this
we’re going t o now analyze everything that we need which is everything that

you see right here. So starting from the top you’re going to see pounde
include IO stream this lot of code right here just simply tells the
program that it needs to include a C++ library known as i o stream which stands
for input output stream.

Now on every program that we write you will need this line of code
which is why I include it in our
skeleton is because you know if you
don’t have this line of code your program will lose its basic input
output functionality. So you do need this line of code and every program
that we write. Moving on you’re going to see using namespace standard.
Now this line of code is not necessary for your program to run.
OK so if we
took this code out right now it should still run fine.
We hit F NAND.
Everything goes fine and we still get the same result process returns 0.
However I do want this line of code in here for reasons that I’ll explain in
the future.
For now just know that we do want to include it as part of our
skeleton because it will make your life
easier when we start writing
more code and I will show you on future tutorials.
But for now just know that you do need using namespace standard
And it does it with the semi-colon on. Right now you’re
saying why does this line of code end with a semi-colon and this one doesn’t.

Well we’ll get to that in future. Toils again.
It’s all going to become a habit. For now just know this.
This is the code that you will need in all of our C++ programs. Moving
on to the next big chunk of code. This right here is known as your main
function and in every C++ program that we write you will need a main
function and type it up. You just simply write I continue which stands
for integer and then main open print close parentheses and then your
brackets with the return 0 statement.
Now in in programming there’s two different conventions for writing
these brackets I want to go ahead
and show them to you now so you don’t
get confused.
Later if I do this one convention is the way I just saw it
which is like this where your brackets are open and closed down here.
But the other way you may see it is like this where your brackets open
at the top and close down there which is fine there is no difference in the
code whatsoever it will run just the same. So I just know that it’s it’s
just a programming convention.
There’s no right or wrong way. Some people have their own
opinions on why they do it a certain way but just know you know it’s all

a matter of preference. So before we end this tutorial on when you go
through and I want you to top this up with me so you can get in the
habit of doing it. So what’s the first thing we need to do.
What we need to include the input output string C plus plus
libraries so we can you know output stuff
to the console window to do
that we’re going to hit pounde include IO stream.
Ok no semi-colon on
this line again.
He’ll get in the habit of no where to put him where not to put him.
But for now you know just no there’s no semi-colon at the end of this line.

Now though we don’t need it for this program. You do one is part of your
skeleton for this class Id want you to get in the habit of writing it and
all of our programs.

So let’s go ahead and do it now. You want to use the
standard namespace.
And how do we do that. Remember we typed using namespace
standard and that one did have a semi-colon moving on the other really
piece of code that we need for our program to run is the main function. And
remember that was preceded with IMT which did for integer. The name of
the function main open Princie is closed parentheses and then our brackets
depending on what convention you decide to use will be different.
And then return the value 0. This right here is working code.
If you take out some of this code sections that this code or return an error it
will not run. So for now just know that everything in this code is
needed and in future tutorials will go into a discussion as to why they
are needed and what exactly they do.
Before we get into the code blocks editor I kind of want to do this
on a notepad sheet real quick so
that we can we can show you I want to
kind of discuss with you how these data types are declared and
what they
mean. So a datatype what is a data type. What is a data type a
datatype is basically a description of what we are using. So for
instance and the real world if we were going to use the this the letter B for
instance. Well this is to us is known as a letter. This would be
the datatype in programming. OK. Or what if we were talking about
the number 7 in our world. This is called a number. This again is
a data type.
And you know if we were talking about programming except in
programming and in C plus plus we don’t
call them letters numbers.

So how what do we call them. Well let’s start with just a single letter.
Let’s let’s just start with the character B. OK. Again this is a
letter but in programming. This is called a character data type and the
character data type. Sorry about that. The character data type is
denoted or kind of encapsulated with single quotation marks. So.
So that’s how. So. And C plus plus this letter B It’s
called character data and you have to declare it with single quotation marks.
And when we get into example code you or you’ll understand what I mean by
declarer with single quotation marks.
But let’s move on to a number. So let’s say 7 in C plus plus
This is called an integer and an integer is denoted just as it’s seen.
quotation marks nothing special. What about multiple letters. You know
what about you know the name Bill. You know that’s four characters but
this thing is a whole what is it. Is that a word you know in in our
world it’s called a word. But what is it. What is it in C plus
plus well and C plus plus it is known as a string which is alpha numeric data.
OK but for now just now it’s called a string data and you denote stream data
with double quotation marks as so.
And I kind of want to go over one last thing. And that’s
decimal numbers so like seven point seven seven you know.
Is that an
integer. Well no it’s not. It’s not a whole number. So
what is that called.
Well in this it can be one of two things you know actually can be
multiple things.
But for this course we’re going to keep it simple know
that it’s either a flow or a double.
OK. And it’s denoted just as
seven point seven seven. For this class we’re going to use the word
double And the reason why is because if you use the word flow when you
declare it as this seven point seven seven behind the scenes in code blocks
code blocks automatically and convert it to a double anyways.
So for now we’re just going to call it a double data type. OK
so let’s move on to some actual code.
OK. And we’re going to practice
declaring these four major data types that I’ve shown you here. Let’s
open up our code.
And by the way the last tutorial the code was I zoomed in if you
couldn’t tell if it was hard for you
to read in the last tutorial.

Hopefully this will make it easier for you to read. So right now let’s
go ahead and practice what we learned in the last tutorial in this project.
I want to practice writing our skeleton so to speak everything we need for our
code right. So we need to do basic input output library.
We need to include it. So let’s include IO stream. OK
we want to use the standard namespace coding. And then we need to
declare our main function and we need a return value for this main
function which as we said we’re going to use 0 and this is our skeleton
This is everything we learned in the last tutorial. Again if he if this
isn’t if you still haven’t got this down yet you know as I suggest because
practicing it over and over until you get it down to where you can
basically do write this code in your sleep to get your program to
compile and Ryan as with process returns zero.
Let’s get into our datatypes and variables. OK. So we
discussed how to do what the data types were you know it’s kind of a
description of what you’re dealing with but what’s a variable. Well
a variable is kind of like a box.
And your data type is a label on that box. That’s how when
you picture this you have a box and then you have a label on this box.
so. So let’s say we put the letter B inside a box.
So the letter B
is character data right.
We discussed this earlier. So to declare
the character data we write C A R which stands for character. OK.
So that’s our label. Character c ha our that we’re putting on our box.
Now our box is user defined meaning we can name it whatever we want. So
I’m going to name it letter because that’s what’s in this box is a letter.
It’s a letter. OK. And then we need to declare what
the letter is. We put a equal sign. I’m sorry about that guys I
don’t know what that is. Pop in to say put that equal sign. OK.
And then again character data is denoted with single quotation
marks and then inside the single quotation
marks we put our letter B and
then end the statement with a semi-colon.
And this right here is
declaring a variable with the data type of character and that variable that
character variable is the letter B. OK so let’s move on. Let’s
let’s let’s move on to the other. Now if you don’t know what this is
used for yet that’s fine. In the next tutorial we’re going to discuss
how we use these variables and what exactly they’re used for.
But for now we’re just declaring them and I’m kind of giving you a
visualization of what they are.
OK so just for now think of them as a a
box with a label and then something inside the box.
In this case it’s a
box that holds characters and in the box is the character B. OK.
So let’s move on to a number of box holds numbers. So in the
end a number is going to be an integer.
If it’s a whole number. So
to declare a whole number integer value we write the word I.A. which she makes
you probably remember from here.
Maine which we’ll get into. Why do you need that again in
future tutorials.
But for now let’s focus on this and we’re going to put
a number in here so let’s call this variable number again it’s user
defined. If I wanted to call it Jimmy I could call it Jimmy.
But you kind of want it you know it’s convention to call it
something they represent.
So we’re going to call it a number.
that’s going to equal the number seven. And you end that with a
semi-colon. Remember no quotation marks right here just the number.
OK. That’s that’s another variable.
Let’s do the other two variables. We did let’s do a let’s
make a variable that holds the name Bill inside.
So to do that we write
suring because that’s the data type remember multiple letters is Alpha
alphanumeric data is called string data. OK. Which you
know I’ll get into it later string. It’s technically a class and I know
you don’t know what class is over now I just know it’s it is a data type
for now. OK. String data.
And we’re going to call it name equals double quotation marks.
Bill semi-colon OK so there’s your variable for a name or multi character data.

OK. Now and in string don’t don’t get it confused with only being
characters for my to do. Bill ’99 hyphen hyphen hyphen semicolon
semi-colon inside quotation marks. That’s fine alphanumeric data will
hold all these characters and this will not cause an error. This is
everything you can keep in this variable that is fine.
So I just know that. But for now actually let’s call it Bill
’99 OK so that you don’t forget that you can actually put numbers
string if you want to do just 99 you could design’s you have to double
quotation marks it’s still string data. OK.
But for now it’s Bill 99. And then for the last data type
Let’s do a decimal number.
Rich remember I said it could be float or
double but for this class we’re going to use double. So it’s a double
let’s call it decimal equals seven point seven seven semi-colon. And all
this is fine if we run this program it will not cause any errors. Everything
runs processor turns zero.
Same outcome. All this stuff is happening behind the scenes
of course you won’t see anything in the console window
when we run it.
Anything different you know you’ll still get the same result process returns 0.
Everything’s fine.

But the point is to just show you how to declare these variables
and data types to discuss what they
are and show that you know if you if
you declare them right you won’t get an error.
Let me show you what will
happen if you if you know if you call this character or let’s say we call
it stirring. OK. Without the double quotation marks.
If you declare it wrong which this is declared wrong because you’re
calling it a string and you don’t
have quotation marks if you want it to
be right you’d have to put in double quotation marks.
But if you take
those out and this is declared wrong and when you try to build and run you’ll
get an error. See this red box and if you look down here in the log you
can scroll down and it says air conversion from double to non scalar
type standard calling Kolins string requested. And that build failed one
So that right there will cause the program to crash. So when
you change that back to double and if we run it again build in around
will go fine. So that’s it for this tutorial.
Let’s move on to the next tutorial.

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