Objective-C Tutorial - Lesson 12: Function Prototypes Video Lecture | Learn and Understand: Objective C (English) - Web Development

what is up guys join here with Objective
C tutorials lesson 12 function
prototypes and we've been going over
functions quite a bit the last few
lessons and you may have been messing
around with the functions that there's
two that we had above main and you may
have moved on below main or something
and if you did that and then you build
and run you get errors and you may be
saying why am I getting these errors I
have all the code right I just moved
them well yes yet all the code right but
you didn't in a way because you didn't
use a function prototype and what are
they will then form the compiler that it
will eventually see the function because
you're delegating part of the
responsibility of main off to this other
function so it needs to know there's
going to be a function there to run what
main is depending on it to run so I this
is the function void spend dollar double
dollars and then everything inside the
braces the function prototype is void
spend dollars parenthesis double dollars
and you put the function prototype where
the function was and then you can move
that function any place in the program
and it'll be fun you can move a below
main and there won't be in ears because
main already knows that there will be a
function there to do what you said spend
dollars would do so it's a real simple
concept but one that you do need to know
otherwise you can get in a lot of
trouble and you really don't know what
well now we'll be going into Xcode and
go over this a little bit in code okay
here in Xcode we're going to be trying
out the function prototypes and this is
the function prototype right here this
function swing just copy and paste that
right here and I didn't tell you this in
the keynote but make sure you do end it
with
semicolon otherwise you'll get lots of
pears and then you can just drag this
function down below main and really a
function pro function prototypes just
give you the freedom to put your
functions anywhere in your program that
you would like to anywhere that you'd
like to put them copy and then paste it
remember end it with a semicolon you can
drag it down below so now you have your
main function right here and then you
have your extra functions that you
delegate certain responsibilities to and
your program don't run sable and as you
can see it belt build and ran correctly
nothing wrong so I know this was a real
quick lesson but I just wanted you to
really understand the importance of
function prototypes and what they can
really benefit you in your program and
they give you a little bit more freedom
to so one more lesson before
object-oriented programming will be
extending this program quite a bit so
it'll be a great lesson and then the
next one after that will really be
getting into programming that you'll
really use for like developing iphone
applications and stuff the
object-oriented oriented not orientated
oriented programming so check out any
lessons that you may have missed some
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