Java Programming Tutorial - 16 - Many Methods and Instances Video Lecture

what's up guys is Bucky welcome to your
16th Java tutorial and in this story I'm
going to be teaching you guys how to use
multiple methods and also something
called instance variables when working
with classes so let's go ahead and open
up our tuna class and clear anything out
if you have anything in there and let's
go ahead and the first thing I want to
do is make a new variable called private
string and just put a girl name because
we're going to be making a program in
the store l2 output the name of our
first girlfriend so the first thing you
probably notice is instead of public I
put private and this is because when
you're working with classes right now we
have two types of variables public and
private public variables any class can
use that variable but when you use a
private variable only the methods inside
this class can use it so the methods
that we're about to build can manipulate
and change and also access to this
variable if we were in another class
like this one over here it couldn't use
this variable in this class so private
means private inside this class only the
methods can use it inside this class so
let's go ahead and make some methods the
first method that I want to make is
public void set name and what this is
going to do is set the name of whatever
we put into it into the variable girl
name so of course we need a parameter
string name so now we have two variables
name and girl name so let's go ahead and
add some instruction for this method
we're going to put the girl name is
equal to name that's all that's all we
need for this method and what this is
going to do this whenever we use this
method in our main program whatever we
put in for the argument for this method
all it's going to do is make sure girl
name is equal to name so it's pretty
much just putting girl name equal to
whatever you typed in next let's go
ahead and make a method to access that
so let's go ahead and put public string
and this is the return type let me show
you
guys in a second again we know public
means access anywhere
the second thing after this is a return
type and whatever your method does it
may or may not return something this
method is going to return a string so
that's why we need to put string and if
your method returns nothing go ahead and
put void so now let's go ahead and our
method body let's go put return girl
name that's all all it does is a return
girl name which was made up here next
let's go ahead and make one last method
totally avoid saying and this is going
to be our final output to the user so
all we need to put here is
system.out.print F and this is a new
type of print if I didn't teach you
before what it does is take something
like your make sure I was felling
everything right your first girlfriend
was percent s and whenever we use
percent asset it needs to know what
string no I want to put in place of this
well we have a perfectly fine string
right here in our get name so let's go
ahead and I won't copy that I won't be
too lazy get name so it's going to say
your first girlfriend was in whatever
girl name is as defined up here that's
what it's going to output you'll see
what it does later but for now let's go
over your apples one make sure you
import your scanner and make a tune
object so we can access that class and
now let's go ahead and just put a basic
prompt on the screen so we can tell the
user what to do system.out.print line
and what are we going to print
I just put print something like enter a
name of first girlfriend here just any
prompt will do just so we're not lost so
the user actually knows what to do
and after that go ahead and we need to
make a temporary variable so we need to
put string temp you can name yours
whatever you want I just name my
template
fun input and this is where we use our
scanner variable the next line with
empty parameters and again whatever the
user types in as their answer it's going
to be stored in the variable temp so
that's what this line does this is just
a prompt this takes whatever they enter
and stores it in the variable temp right
there next we need to do something with
this so let's go ahead and use our tuna
object and we need that to access set
name and of course the parameters for
this is going to be that temporary
variable temp so what it's going to do
is take the name that they entered and
set it equal to girl name right here
it's going to take it which is name set
it equal to girl name now we need to do
one last thing now that we've got that
name equal to girl name all we need to
do is do tune object-- saying with empty
parameters and what this does is use the
tuna object saying what is this you may
ask the saying just outputs on the
screen arm your first girlfriend was and
it's going to be whatever they typed in
for the name so let's go ahead and run
this see if I got any errors and I don't
so let's go ahead and enter name of the
first girlfriend mine was Kelsey go
ahead and press Enter and it says your
first GF was Kelsey stands for
girlfriend she was babe so let me tell
you guys what this does one last time
import scanner we know what all this
stuff does and your name what this does
is allow us to enter a name and it's
going to store it in that variable
called temp and what the next line does
right here is say alright in your class
tuna take that variable temp and use it
in the setname method so now it takes
that variable name temp which was Kelsey
and stores it as girl name so now girl
name equals Kelsey so it says all right
now what well next I want you to just
use the saying
method in the class tuna so it says all
right we know that girl name is equal to
Kelsey now so now we can use that saying
what you told us to do right here and
just your first girlfriend was Kelsey
and again if you don't know what printf
does then check out my C tutorials and I
go over this this is the common print
function in the language C also you can
use it in Java but this is just another
way to print so don't let it confuse you
so that is how you use um instance
variables and multiple methods so again
you can use multiple methods in the same
class
and don't forget whenever you have a
variable that's outside a method again
it's outside all these but it's inside
this entire class it's called an
instance variable so that's where I get
that name from so I hope you enjoyed
watching this tutorial I hope you
understand at least a little bit of it
so thank you guys for watching make sure
to check out my next story I promise
I'll be clearing this up for you don't
forget to subscribe to my channel and I
will see you next tutorial