Terrific Text Part 2

This is just a screen grab of our interactive coding talk-through, prepared to make captioning and translation easier. It is better to watch our talk-throughs here:
https://www.khanacademy.org/cs/programming/

So now that we learned how to use text,
let's get a bit more fancy.

The first fancy thing is that now we're

going to start using the word "string".

You might think, "String?
That's what my cat plays with."

But for programmers,
string is a special name

we use for bits of text.

You can think of it like
a string of characters, if it helps.

Your name is a string,
your school's name is a string,

and every text message
you've ever sent is also a string.

Basically, just think, string equals text.

So we used drawing
and coloring with strings already.

Could we use variables
with strings? Of course!

Just like you might normally
put a number into a variable,

you could also put a string
into a variable.

We just say something like,

"var myName = (whatever your name is)"
so "Sophia";

remembering those quotes.

And then we put the variable myName

into the quoted text
instead of writing "Sophia" directly,

like we were doing before.

And this way though it
looks the same right now,

we can actually,
write this multiple times

you know, one time there, one time there,

you know maybe we
can be a little artistical.

And then all you have to do
is to change this one variable

to be your name, and then you have

your name written three times.

So, just flipping that back,
what if we want to get

kind of crazy, can we
start adding together strings?

Like you remember when we maybe
started adding together variables?

Well we can actually do that,

the computer will just
stick the two strings together.

So for example, you know,
we can get rid of this,

to do it only one time
and then we can use this other variable

message that's going to be my name,
plus say a bunch of exclamation marks.

And if we stick message into text
to draw this variable

instead of my name,
we can see that

all it did is just stuck those exclamation marks

that we had onto the back of my name.

And we can even make this
a little bit more exciting,

if we wanted to write message, say, twice.

So this looks pretty reasonable,
you know adding strings means

you stick one string
onto the back of the other string.

But you might be thinking,
can we get really crazy?

And start multiplying or dividing
or subtracting strings?

Could we do that? Well no we can't,

with strings we can only add them.

You're right that we could divide
and subtract with number variables,

but string variables only allow us to add.

But still being curious and asking
those sorts of questions,

is the right attitude in programming.

You might think, "What would
it mean to divide a string?"

So we can also use animation
and mouse interaction with text strings.

For example, we can make the string
follow the mouse around.

Just by sticking it in a draw loop
like we did with the rectangles.

So if you think about how to do this,
we would say var draw,

and then we'll stick all of this, right in here.

This probably looks really familiar,
from "intro to animation."

And you might think, alright, well to
make it follow the mouse around,

we certainly need to use
mouseX, and mouseY

and there you have it we're
actually painting with our name.

And of course if we wanted,
we could easily set a background,

say to, you know, a nice light blue.

And now we have that the text
is just following the mouse around,

just like we saw with the rectangles.

And now as a last fun trick,
let's use animation,

and make the text size
grow and grow and grow.

So, here we're setting the textSize to 30,
as we learned in variables

instead of using 30, we could also say,
var howBig equals 30;

and then use this variable
instead of doing 30 directly.

Well that's the exact same thing,

and we need to obviously
be changing something

in order to get an animation.

So we can do that by saying,
how big equals how big plus one

which actually means,
if you remember howBig gets,

you know how big it was before,
plus one to make it a little bit larger

and now we just need to
restart the program,

and here we have that
as we're moving the mouse around,

the text size is growing and growing
and growing and growing

because of this line right here.

And you know, just on your own,

you might think, okay how
can we make it grow faster?

So now, not only do you know how
to manipulate shapes with code,

but you can also use text with code as well.