Objective-C Tutorial - Lesson 11: Part 1: Scope of Variables Video Lecture | Learn and Understand: Objective C (English) - Web Development

what is up guys Jordan here with
objective-c tutorials
lesson 11 scope of variables unions and
and numeration now the first thing that
we'll be starting off with is scope of
variables and this is a important thing
to grasp we've already kind of learned
about this indirectly but now I'm going
to totally and fully explain it
variables are not available to every
part of your program we've been working
with variables that are only available
in the function which they are declared
and they're and these variables that are
only usable in the functions that are
declared in are referred to as if their
scope to that function and to get access
to a variable from any function you must
move the declaration to file scope which
is just in the file not in any function
and then when you move it into the file
you can have access in any function to
it so now we're gonna be heading into
Xcode real quick and I'm just gonna show
you exactly what I mean if you don't
already understand okay here in Xcode
I'm just gonna move this struct variable
right here from the file scope into main
and if what I said in the keynote is
correct it should get errors when I vote
and run so let's see yes they are there
are errors and it's because they're
undeclared because this function doesn't
have access to a budget a vacation
budget because it was declared in Maine
not in this function and it wasn't put
in the file scope so here if we just
simply move it into the file so it's now
scoped to the file so all the functions
have access to it save all bill and run
everything works perfectly so that's
also why we declared the structure in
the file and not in Maine or another
function is because you're using the
members of the structure and the various
functions of the program so we kind of
went over
just before indirectly because I had you
put all this stuff outside of mein when
we built it but I didn't quite go in
depth as exactly why we're doing this
but now we're gonna jump back in the
keynote and bring go of reunions and
enumerations