Java Programming Tutorial - 46 - Static Video Lecture - Java Programming

what's up guys welcome to your 46th Jeff
tutorial and in this tutorial I'm going
to be going over what static variables
are and how they're used
so usually whenever you have a class
that has objects each of the variables
um each objects has its own set of
variables like first-name and I can make
um an object called Bucky in it would
have its own first name Bucky and I
could have another object named Tommy
and it would have its own first name of
Tommy but sometimes you want all the
objects to share a single variable for
example if you're going to make members
of a club and you're going to like have
the club count how many members were in
it for example if I was in the club it
would be 1 if tommy was in the club it
would be if me and Tommy we're in the
club it would be - if me Tommy and Megan
we're in the club it'll be 3 and we each
don't need to see that we shall need an
updated variable or a separate variable
for 3 since the members in the club is
all the same so for example there are
some variables that you just can share
and you're saying alright why don't you
just write a separate variable for each
object and update it well that sticks a
lot of time in space so you'll see what
static is by the end of this tutorial
and it's one of the most useful things
that I actually taught you so far so
listen up in this story we're going to
be building a club of course and the
club is going to be of hot girls that
would like to go out with and yes they
will be famous and no I will never go
out with them so let's go ahead and make
a couple regular variables first for
each object it gets own private string
and let's go ahead and put like first
the first name and then go ahead and put
private string and last for last name
and now we need to give them a variable
that they can share so go ahead and put
private and put static and that static
keyword means that every object shares
the same variable so when this one
changes it changes the all objects in
before if you change one object's first
name not only that object's first name
change
but when you change a static variable
they change with all objects so if I
change this to four then all objects
would see four got it good so static int
and we'll have members of our club and
we'll initialize the zero so without
building anything we have zero members
in our club so next let's go ahead and
make our constructor so public our class
name is tuna and it's going to take two
arguments string first name is string
last name this is how we're going to
insert members in our club and in our
constructor just put first equals first
name last equation to our members
variable so after we add our first
member members will equal one when we
add our second member members will equal
two so next let's just go ahead and
system.out.print format and our format
will be something like again you can be
creative with this if you want umm
constructor for make sure you spell it
wrong % s % s so it will be constructed
for Bucky Roberts and then we'll have
members in the club and then put like :
% d and then a new line so we're going
to have like constructor for Megan Fox
members in the club one constructor for
natalie portman members in the club too
easy enough so now we need to put first
of course last and members and I spelled
that wrong I mean be ers members members
that's a pretty catchy dude alright now
let's go ahead and write some more
methods that are going to come in handy
first we need something to get their
first name so public actually let me
think about this
for this tutorial I'm teaching you is
constructors right so we probably don't
even need these yet but we sure do in
the next tutorial
so let's go ahead and end in this apples
and in our main function right here
let's go ahead and make some members so
let's go ahead and make member one tuna
because this is into class member one
and we'll set it equal to new to none in
the course it takes the arguments again
you can see what arguments it takes by
this constructor over here a first name
and the last name so the first name can
be megan in the last name of girls I
want a date club can be Fox
so now what we should have outputted on
the screen is all might as well just do
it constructor for Megan Fox and members
in the club one easy enough so let's go
ahead and make another one now tuna
member to make another object equals new
tuna and we'll have something like
Natalie and then Portman you don't know
who she is definitely Google it and
let's go ahead and make one more from
tuna member 3 equals new tuna and let's
see let's get us
let's get Taylor she can join the club
too and Swift she is babe with a pretty
voice hottie with body cutie with booty
anyways so we made three different
objects each one well let me run this
show you guys that works show myself
that it works so we made three different
objects right here one for Megan Fox
named member one one for Natalie Portman
named member two and one for Taylor
named member three each of them has
their own set of variables let's look at
this one natalie portman member number
two for every object they have their own
set of variables right here natalie has
her own first name right here and she
has her own last name of Portman right
here but they all share this members
variable and they cannot like Megan Fox
this object
she can't see what now these names are
but she can see the members in the club
has changed it to
and when Taylor Swift joins the club
right here since its static it means all
of these objects share the same static
variable so they can all see that the
members of the club has changed to three
so that's why static variables are
useful since you know sometimes you just
need and again if you didn't have this
on a nutrient art right here
you would have to have a function to
update all of these each time but you
know why update three separate things
one two three and then when a member
leaves you have to update three Sep
things one two three when you can just
have one variable call it static and
update at one time so that's your quick
tutorial on what static is and why it's
useful it pretty much instead of having
to update it many times you just call it
static and all members or objects can
see it so thank you guys for watching
this tutorial if you don't understand
you go in next tutorial because we're
going to be going over static some more
but like I said thank you for watching
don't forget to subscribe and I'll see
you next time