Objective-C Tutorial - Lesson 22: Part 1: NSNumber Object Video Lecture | Learn and Understand: Objective C (English) - Web Development

what's up guys join here with Objective
C toros lesson 22 NS number object now
before I really jump in to this lesson
I'm going to go over a few basic things
about objects now soon our objects will
be sending messages to other objects to
help them accomplish whatever they were
created to do and you won't need a to
write all these objects yourself because
a lot of them will come from the
frameworks specifically a coca
foundation class that's a lot of where
the objects will be using will come from
and in this lesson obviously I go over
then it's number object and all the
types that go along with NS number
object I go over them in lesson two so
if you kind of got a little shady on the
types like float integer all that stuff
or if you never even saw that lesson go
ahead and check that out after a link
down the description anyways I'm just
give you a heads up in future lessons
probably the next two or three after
this one I'll be going over array as an
different types of rays and everything
but anyways on to NS number now we're
going to be now transitioning from
numbers as variables to numbers as
objects and actually pretty much
everything will be using in our program
will become objects and some of the
things may be a little surprising to you
and one of them may be a NS number
because you may be saying well shouldn't
just shouldn't a number be just a
variable I mean it's so simple I mean
it's one digit or maybe multiple digits
but obviously it's just a number you
know I mean it's not a complex thing but
yes numbers can be objects and some of
the reasons why pretty much everything
will start becoming an object is some
really deep computer science that I
really don't even understand and a lot
of it also is for practicality because
to use the arrays that we're going to be
talking about i know you probably don't
know what a ray is but to use another
programming element there to use this
other program element that we'll talk
about in the next couple lessons we need
these we need these numbers to be
objects instead of variables so that's
why we're going over this lesson and
learning how to transition them from
variables to objects no just refresher
we've been using the double type of
variable for pretty much all the numbers
in our program so far now how do you
create this NS number object well if you
look there real quickly at that a budget
that we created couple lessons go not
sure which one right off hand but
anyways it's based on the budget class
as you remember that that class we
created and it's called a Europe budget
and we had that asterisk there because
it's a pointer to the budget and then we
send it a non new message and that new
message actually does a couple of things
and I'm not sure if I actually went over
this in that lesson but it actually
allocates memory for the object and then
it calls the initialized method and it
initializes everything 20 now in that
budget that we created in last lesson
that really doesn't matter that it
initializes everything 20 but in this
nsnumber object that's the big thing
because um we will just go through the
NS number that little method there that
we use to create the object we have NS
number because it's based on it is an NS
number so we had the a strict again
because it's a pointer to this object
it's called number dollars in Europe
then we have the equal sign the brackets
and everything NS number so we're going
to allocate an NS number allocate space
and image for an S number object and
then we're going to initialize it and so
basically we just take the new method
and we just split it up and manually do
everything this is
new method but we initialize it with
whatever number we want we cannot use
that new method because if we did all
our numbers would be zero and obviously
that kinda feats the purpose of having
different numbers that they're all just
zero and we actually specify the type
that we're going to initialize it with
so we say in it with double and then we
put a double value their clothes off the
brackets put in the semicolon so that's
why we can't use the new arm message for
creating this object we have to actually
allocate it and initialize it ourselves
now there's actually a couple other in
it methods for NS number you can
initialize it with a double and a juror
float a bull character all that stuff um
it's the same basic idea just wanted to
go through those real quick now you can
actually convert these NS numbers so
that's another cool thing about NS
number you can convert it from one type
to another and how you do it is you just
send it this message whatever the name
of it is the name of this NS number is a
dollar and we're going to now convert it
to an int value so it could have been a
float or double whatever now it's going
to be converted to an int value simply
with this little message and you'll also
be using this when the NS number is an
AH is an argument and when u Zen s
number and NS log so down below there is
an example of NS number as an argument
um in the method declaration there
instead of double in those parentheses
you see NS number and then of course
it's a dollars in the name of it and
then down below when we subtract and
then reassign that dollars of value to
budget instead of just having straight
dollars you have to put in double value
because whatever that value that's going
to be passing through
argument it's a double value set you
have to specify that because all the
compiler knows from that method
declaration is this is an object type
that's pretty much all the NS number
says it's like just putting variable in
there if back when we just used double
and before we specify the type this way
we're just saying what type of general
category variable or objects so that's
why you have to do it down below now
factory method this allows you to create
an object without using the out the
allocate and in it messages so it's kind
of like a new in a way but you can
actually specify the number like the
value so it relies on the class for all
the initialization so um down below is
the old way that we just learned how to
create the NS number object and then up
and they're above is the new way so you
have n is number and then the name of it
the asteroid all that so it looks pretty
much the same but you only have a one
little message so you say this is NS
number and it's a number you say number
and then with double with flowed with
int whatever and then you put that
number there and then you close it all
off bracket semicolon all that good
stuff now there's a shorter way but it
also has some memory management and
issues and I know we haven't talked
about a memory management at all I don't
think but we'll be getting into that up
and the future lessons way down the road
but yeah it has some issues as far as
memory management so we're just going to
be using the first way that we learned
how to create this nsnumber object using
the alloc and init with double in it
with internet with float those two
messages now we're going to go ahead and
jump into Xcode and convert some of the
variables into an nsnumber object
Oh