Objective-C Tutorial - Lesson 19: Splitting The Program Into Separate Files Video Lecture | Learn and Understand: Objective C (English) - Web Development

what's up guys john here with Objective
C tutorials lesson 19 splitting the
program into different files and you may
be saying well why do we have to split
it up into separate files and everything
why can't we just keep it in one file to
a whole lot easier to manage right now
well true right now it is but when you
get a large program with many classes
it's very very consolidated and hard to
manage once all in one file so this is a
mainly something that's done to help the
programmer really just manage the
program in the developmental stage and
also because the classes are naturally
split up so go ahead and open up the
program that we've been working with and
as you can see you have the interface
and the implementation so it's that
natural kind of divide of the class so
anyways the first thing we're going to
do is we're going to go to project and
we're going to create a new group and
just name it classes and make sure it's
not under source or any other file and
now what we're going to do is we're
going to create two new file so go to
Xcode and then go to file new file
and make sure that it's under cocoa
glass and you select an objective c
class and it's a subclass of nsobject
and hit next then go ahead and name it
budgets incessant in the class and make
sure that checked is also create a dot h
that also create that header file along
with the implementation file and then
hit finish and then it'll put it right
here in classes if it didn't
automatically put it in class and just
drag it into the classics folder but now
what we'll do is go into the budget
object got in and copy command C and
then you just delete that up and then by
default on some code is in this header
file the import cocoa which I'll go over
in just a second and then this empty
interface so go ahead and then just
delete that and paste in the interface
that we copied from budget object on it
but why does it say import cocoa instead
of import foundation well because Xcode
automatically assumes that we'll be
needing cocoa for iphone or mac
application so it automatically imports
it when we add a new objective c class
and AH cocoa also brings along with it
the foundation header file so there's no
need to switch cocoa to foundation
because Coco's bringing in everything
that we need from foundation so now the
next thing we need to do is go back to
budget object and grab the
implementation here copy
and do a cup and then delete and paste
and take note that budget m imports
budget dot H so it imports all the
information from the interface into the
implementation but now we just have one
last thing to do you can actually delete
this import here because we imported it
right here because we imported cocoa and
cocoa brings along with it like i said
foundation so instead of importing
foundation again which would be
unnecessary we actually need to import
budget dot H because otherwise this file
would not know what we are talking about
when we try to use these methods so
import thank rotation budget H close out
the quotation and then you can go ahead
and build run and stable okay now as you
can see it build and rant correctly so
we split up the class and separate files
and it's a whole lot easier to work with
because you have your interface and dot
H file you have budget da 10 or the
implementation the dot n you have all
the work being done as far as the
objects and messages in Maine it's just
a whole lot easy to manage and
especially when you start getting lots
of classes in your programs it's very
very hard to manage but that's all for
this lesson next lesson we'll be going
over naming conventions of objective-c
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I