Java Programming Tutorial - 42 - toString Video Lecture | Java Programming Fundamentals: For Beginners - Back-End Programming

what's up people welcome to your 42nd
java tutorial and in this tutorial I'm
going to be going over a built-in method
that Java has it's called the two string
method and I'm going to show you guys
what it is and why it's useful and we're
also going to be building part of a
bigger program on this prep it going to
be a two-part tutorial so um pay
attention and it's going to be sweet so
the first thing that we're going to need
to do is get three variables and they're
all going to be private and they're
going to be month day and year so
private int month and just go ahead and
copy and paste that take advantage of
our laziness 12e control V int day and
private int year so now we have three
variables right there so let's go ahead
and do something with them the first
thing that we're going to want to do is
build this pop pie again you can see my
pot pie class so I'm going to build the
pot pie constructor so go ahead public
and just go pop pie and it's going to
take three arguments it's going to take
int
m per month in 2d for day and Y for year
again you can name these anything you
want not important but remember to set
your variables which were your private
variables like month
equal to whatever you are corresponding
letter I just put MD and y for obvious
reasons so that private date variable is
going to be set to whatever we pass in
for D and that private Y is going to be
set to whatever we passed in for Y so
now we got our constructor but we want
our constructor to do one more thing we
want it to print out a string so and we
just want it to print out so it can know
so we can know that our constructor
worked or didn't work make sure you put
an equal sign right there so let's go
ahead and system.out.print F we can just
print format
and I already started filling them in
for us so let's go ahead and print out a
string so let's put um Quan house but
the director make sure we spell it wrong
for this is and then we'll go ahead and
put percent s and that means string and
then go ahead and put a new line if you
feel like it if you don't feel like it
you know you don't got it and now as you
can see right here our C style format it
takes one string argument
so in our second argument just go ahead
and write this and when we write this
what it means is this the key word this
what's highlighted right now this is
just a reference to whatever object we
just built whenever we call this class
so it's going to say alright then what
the heck do you want me to put for a
string well that's what we're going to
be going over in this tutorial right now
anytime that you need a string
representation of an object Java built
this thing called a two string method so
let's go ahead and write public and
we're going to be building that right
now public string to string and I know
month is most of the time you can call
your methods anything you want but you
can't you have to say to string in this
case and go ahead and it takes MC
parameters and in your body of your
method go ahead and return whatever
format you want so return string format
and then go ahead and % go ahead and %
WTF does that mean go ahead and put this
um I mean you can write in whatever
format you want but just follow on
percent d % d % d that's the common date
format and that has the month day and
year so the month / day / year /
so this is what this is going to do well
let's go ahead and finish our tutorial
and then you can probably see what it's
going to do then I'll talk you through
it one more time what we need to do is
go ahead and create an object now and
I'll call it pop pie and I'll just call
it like something like pots object that
pop object is not important
and then whatever new pop pie and I know
I should have like proper months and
days and years but I should have four or
five six six seems like a good year a
long time ago so now that we go ahead
and create this object we should get a
nice little string at the end if I
didn't mess anything up and it says the
constructor for this is four five six so
now let me take you guys through exactly
what I did what I did is create an
object using the parameters four five
six so let's go ahead and look what
happened when I created that object it
said alright since the first thing I'm
going to do is this constructor I'm
going to pass the parameters four five
and six and four month was equal to four
day was equal to five in year was equal
to six what the constructor also did is
say alright every time I create an
object I want you to print out this
string but we had in the string variable
instead of an actual string we had a
reference to an object and anytime you
reference an object and it needs
something in the string format it looks
to this method right here
what this method says is anytime you
need a string representation of this
object you look to me I'm two string I'm
built in Java that's what I'm for so
that's why it outputted this right here
the constructor for this is four or five
six this is where that format four or
five six comes from right here and in
the next tutorial if this seems kind of
confusing I'll show you guys a useful
way why to string is actually used and
not only you know it might be a little
confusing to understand I mean this is
just an example it doesn't really
anything but in the next tutorial I show
you guys I'm like one example where we
would actually need it and use it but
for now hopefully you get the main idea
again the key points is the probably two
things you're going to be confused upon
is this
I mean what's highlighted right now any
time you use that key word this it's a
reference to the current object so it's
going to say all right just reference
the curring up the current object so it
implies that it needs a string so since
it needs a string it says all right I
need a string here says oh I see
that's why you gave me this two string
method so anytime I need a string I know
where to look
so makes sense and if it doesn't it will
in next tutorial but for now thank you
guys for watching hopefully understand
the basics of a two string method and
don't forget to name it two string
that's very important so again thank you
guys for watching and I'll see you next
door