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So let's take a closer look
at what we just achieved

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especially around the text
we printed to the screen.

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We're going to learn about two new topics,
strings and variables.

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In Java, by placing letters or

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characters in double quotes,
we create what is known as a String.

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A handy way to visualize strings,
is by picturing a banner that you might

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hang at a party, that is stringing
together individual characters.

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Strings are how we deal with text and

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you'll encounter them quite a bit
in your programming adventures.

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In fact, since strings are so

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common, they're one of the basic
data types that Java offers.

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A variable is a way to store data into
a named location that you can use

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to reference later.

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In Java, you must specify what data
type you are planning on storing so

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that it knows how to store that
information, String is one of those types.

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And we'll discover more data types as this
course progresses, when you need them.

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If you just can't wait, I've also
added a link in the teachers' notes.

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Let's go back to our workspace, and
let's learn how to use a String variable.

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All right, so let's say I asked you to
write out another line to the screen that

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said, Craig is learning how to write Java.

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It looks something like this,

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it's console.printf(''Craig is learning

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how to write Java'');,
now let's save that.

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Let's go ahead and
compile and once again we do,

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javac Introductions.java,

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that creates the class file and
we say, java Introductions.

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Well, that output looks a little bit ugly.

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It can definitely be prettied up by
putting that information on different

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lines, but how are we gonna do that?

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Now obviously,
if I press Enter in a line like this,

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it's gonna probably break the program.

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So what we have is there's a new thing
they introduced called an escape sequence.

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And that is a \n.

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And that is the new line escape sequence.

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I'm gonna put that at the end
of both of our lines and

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escape sequences are used to write
characters that are not easily printable

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or may break the syntax or
the structure of our code.

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Let's go down here and
let's clear the screen.

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And you can do that by typing clear and
we'll clear our terminal.

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See, it's reset back now and
let's go ahead and let's compile.

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Now I want to show you another
little terminal trick here.

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If you press the Up arrow,
it's going to go and

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go through the history
of what you've typed.

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So let's get back to where we said,
javac Introductions.java.

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We’ll run that, whoop,
look I forgot to save.

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You come up and you press Save.

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No, again let's go Up arrow.

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Introductions, and
let's run it, here we go.

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That is much better looking and aside from
talking in third person Tarzan speak,

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this is looking much better.

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All right, so let's assume we wanted to
make this program about someone else.

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And one way to handle that would
be to change every String that

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contains your name.

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But imagine that our
program got much longer and

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the name Craig is in hundreds of
thousands of places in the code.

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We wouldn't want to have to
change that name everywhere and

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keep changing it everywhere.

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So a better way to handle this is to
store that information in what is known

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as a variable.

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So the way that you declare a variable
is first by defining its type.

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And since we know we want to have
a string variable, say String.

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And next we want to give it a name that
we can reference in the code later.

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The better we name our variables,

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the more likely someone reading our code
will be able to understand its purpose.

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So in that case,
let's name our variable firstName.

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Now we do an equal sign, and
then double quotes, and your name,

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and then of course a semi colon to
mark that this statement is over.

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This reads as assign Craig to
the variable firstName of the data type String.

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In Java, while not required,
the standard for

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naming variables is to use
what is known as CamelCase.

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The first letter is lowercase, and

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then each new word starts with
a capital letter, like this.

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thisIsAnExampleOfCamelCasing.

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Earlier when I introduced you to
the printf method on the console object,

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I said that it was for printing text.

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But, to be more accurate,

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it actually prints formatted text
that's what the f stands for.

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This lets us be more creative with
our text, using variables and

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other special formatting instructions.

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It turns out that printf takes
multiple options or parameters.

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The first parameter that is
passed to the printf function

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is what is known as the format string.

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When using methods, you can add additional
parameters by separating them with a coma.

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Those additional parameters are used
to replace the format specifiers

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that are in the format string.

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Let me show you what I mean.

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First I'll replace Craig with the format

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specifier %s where s stands for string.

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00:05:09,881 --> 00:05:14,879
And then, after the first parameter here,
I'm gonna insert a comma,

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then I'm gonna put in
a firstName variable.

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Let's do the same for the second sentence.

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So we'll replace the Craig with %s.

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And we'll get to the end of the line here,
and

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we'll put a comma in the second
parameter argument is firstName.

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Okay, so let's save that.

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Let's do a clear,
we'll use the Up arrow to get

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back to our javac Introductions,
so we'll compile the program.

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00:05:43,885 --> 00:05:46,826
We'll run the program,
great it still works.

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00:05:49,311 --> 00:05:53,590
Okay now let's change the value of our
firstName variable to a friend of yours.

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I'll change mine to a fellow
teacher's name, Ben.

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00:05:57,552 --> 00:06:03,168
And I'll save the file and
we'll do clear, run javac and

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then we'll run Java and
we'll see that I only

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changed the one place,
but we updated both lines.

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Great job using strings and variables and
formatters even, for that matter.

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00:06:18,440 --> 00:06:23,950
So we learned, when you create or declare
a variable, you first use its data type.

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In this case, we used the data type string
and then we assigned with the equal sign

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and set the firstName variable
to the String, Craig.

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We created that String by
surrounding it in double quotes.

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And of course we end our
statement with a semicolon.

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So that is the syntax or
structural rules for creating a variable.

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00:06:46,860 --> 00:06:51,327
One thing of note here is that Java is
case sensitive which means the case,

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is it upper case or lower case?

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It makes a difference.

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Now let's do an exercise and make sure
all this new information is sticking.