Java Programming Tutorial - 39 - Multiple Constructors Video Lecture | Java Programming Fundamentals: For Beginners - Back-End Programming

what's up guys welcome to your 39th job
tutorial and in this story I'll be
talking about overloaded constructors
now you guys already know what a
constructor is it's pretty much a method
with the same name as that class and
whenever you create an object it
automatically calls that method or does
that method so I told you guys how to
build a constructor and I told you guys
that you can build only one constructor
with the same name as the class but I
didn't tell you guys that you can build
multiple constructors in depending how
many arguments you have it picks what
constructor to use for example if you
called that object with one argument it
would have a constructor for that if you
call it that
um object with three arguments it would
have a constructor that took three
arguments so let's go ahead and do this
right now so we first need our three
variables private int hour and then we
need that same thing let me put a
semicolon instead of colon we need that
same variable with minute and second
minutes and second now let's go ahead
and build our first constructor and we
do this by putting public tuna since
tuna is the name of the class and I'm
not going to have any arguments for this
one we're going to do one with zero
arguments one two and three so when you
put one with zero arguments what we want
to do is eventually we want to give it
three arguments so what will you do is
put this keyword and what this does was
is pretty much invoked the constructor
again but give it three arguments this
time using 0 0 and 0 so now we need to
build another constructor so public
actually we can probably just copy this
copy Relays E and paste public tuna but
instead of zero arguments this one if
they pass in one argument what are we
going to do well if they pass and one
number then let's just assume it's the
hour so we put this hour so if they
passed in object
five it's going to be five o'clock than
zero zero so now let's build another one
and this one's going to have two
arguments this one's going to have an
hour and minute so int hour and minute
right there so now what we want to do is
invoke hour and minute and again what
this is going to do is call this
constructor again but pass it three
arguments right here so now I have
person all right if we call this
constructor again it's going to look
through this one see where is there's
three arguments that look through this
one see where do these three arguments
and look through this one see where the
story arguments and that's why I'm
getting X right here it says the
constructor tuna in it is not to find
because we keep calling a constructor
with three arguments what we didn't
build one yet so let's go ahead and
build one right now let's go ahead and
put public tuna and I could have copied
that but in our in minute int second and
if you watch all my X's just disappeared
so you see there now up and then once we
finally build on it disappears so now
that we have a constructor with three
arguments we can go ahead and build
something what it does in fact I'm going
to build another I'm going to have it
call another method right here that sets
the time to our minutes and seconds and
we're actually going to be building this
and the next tutorial actually we can
prep a builder right now we have enough
time but let me explain you first what
this one does if a user was to create an
object with zero arguments it would give
it three arguments by default so it can
go down here to this constructor if a
user was to enter an object with two
arguments
it would go to this one it would use the
first number is the hour the second one
is minute and the third one is zero and
then it would call this constructor
again with three arguments and the only
one with three arguments is this in our
in minute is second and then what this
constructor does is set the time in a
set time
you're saying all right where the F is
that method well we're going to vote it
right now
so take it easy let's go public void set
time and as the arguments again what we
want to do is take three parameters an H
into m per minute and into s for seconds
now in the body scroll up a little bit
there we go not bad and the body what do
we want to have to set the time well
actually we're going to be building
three methods for this as well and I
know it gets confusing but set our and
this is going to take an hour set
minutes and this is going to take a
minute and set a second and this is
going to take a second parameter and now
once you close this it says the method
set minute is undefined and we're
actually going to build three I mean
let's see six more methods I think we're
going to build methods for setting each
of the times and why do we need a new
method for set our new method for cent
minute and set second well we can't just
have any hour they type in um we need to
build a method for it like last time
where we set the hour we had to check if
those between 0 and 23 or 24 and set
minute we need to make sure this is
between 0 and 60 and also for set
seconds and we're also going to make
make another method for a get method I
mean I not get method for get our get
minute and get seconds and that's just
going to return everything but we're
going to be doing that next tutorial but
if you don't still don't know why I'm
having set separate methods for these
it's so only these methods can access
the hour and down here as I said in last
time we don't want any other class that
have access to this information right
here so that's why we need to build a
separate set and get methods for each
hour in
um like hour minute and second but
anyways that was supposed to be for next
tutorial that was just a little jump
ahead
the meet of this tutorial that I want to
tell you is right here um let's see yep
these are all constructors right here
one with zero arguments one with one two
and three and I just want to tell you
that you can build a different
constructors depending on how many
arguments you have that way you don't
really need the user to enter one
specific set of information
it varies and then depending on how much
information they entered it does a
certain task so if you don't understand
this I promise in the next on either one
or two tutorials this will make all
sense once we finally build our program
and you can see what's going on but
thank you guys for watching make sure to
write this code right now and again like
I said by the end of these tutorials
you're going to understand why we did it
and how this all works
but for now thank you guys for watching
my tutorial on overload constructors
don't forget to subscribe to my channel
it is the best channel ever again thank
you guys for watching and I'll see you
next time