Advanced Fortran Programming : 014 : Rules on procedures Video Lecture | Introduction to Fortran Programming (AdvancedLevel) - Database Management

hello guys my name is Aaron and welcome
to my channel this series is a series of
tutorials on advanced Fortran
programming now this tutorial is more of
demonstration tutorial I think you want
to understand what I mean here but here
we're not looking at any specific
concept today but rather we'll be
looking at some conditions that are that
possible inside modules and programs as
to what kind of allowances they have and
all and to make this possible what I
will be doing is that I'll be just
passing the videos once you know
everyone to write code immediately and
show you guys something
okay okay today okay I'll explain you
guys what what I'm actually what I will
do here today what I'm going to do is
that we'd be looking at these things
okay
can afford we can afford the pause
function have a subroutine and function
defined inside them what about a module
like that and can we saw that some
functions and subroutines can call each
other okay but with little conditions
and all but can one can functions having
within them aren't the set of functions
is that possible okay similarly can a
subroutine have a kind of subroutine
have functions inside them or other
separate subroutines inside them
similarly can functions of other
subroutines and functions in the other
okay is it possible and can it call out
of the program inside it can can there
be a function inside that can be module
inside another function subroutine
that's something we look at and
similarly no module we saw that the
functions of subroutines can be placed
inside but yeah but can a program be
called inside and inside a module can
you have another inside module and off
we will be checking this and to explain
all this to whether we work this out or
not I'm going to have acid when we go
very work this work this out and in this
program over here we'll be checking
which can be done which cannot be done
okay and so in programs
okay so I'll write this in programs okay
let's see let's do let's do with this
now this module is written out children
outside the program definition over here
but it doesn't matter even if you riding
with in the same file or in a separate
file doesn't matter as long as they're
compiled properly it doesn't matter okay
now let's look at the rule of a module
the module is written on the top of the
program as a program is only here and
this program module has one sub protein
called as hello and which prints nothing
but it just prints a simple prints test
simple print hello sleeper that's it
nothing more nothing less
okay and if you want to use this module
I wrote I wrote use hello one because
it's money names hello one and I have
value suggest to just to fill the code
nothing more and I call this hello
function here suppose if I were to run
the compiled build and run this there
turns out to be fine okay now this is an
interesting okay this isn't interesting
now why don't we call this module why
don't we call this module inside the
function okay
sorry inside the program now do you
think this will work
no it apparently does not you're just
throwing it just says that it's there a
lot of just says that cannot change
attributes use associated symbols hello
one and all so let's do one thing let's
comment this out and since if you want
the visa that you have to use contains
have to use contains and stuff contains
to include a subroutine or a function so
by our intuition let's see whether this
keywords contains is needed but when a
keyword click contains is used then the
external definition the external the
definition for the module or subroutine
or may not be needed functions like that
we use for function may not be needed so
I think this lesson we don't need this
okay
now let's run this it's still showing
another it's just showing an error that
our next part of implicit
something okay okay so let me remove
this run this again okay it says there
are next but it contains intersection
okay remove this again if you were to
come by this again okay now it shows
that our next written module inside so
there are issues so you cannot put
modules inside okay this is still
turning out to be never okay let me do
something about this let me use this
let's see if this turns out to be fine
now it just shows that it just shows
that it's still showing a lot of errors
mister it says it still showing that
this is an error and this is not
available at all okay now let's do one
thing let's cut this module I am extreme
am completely experimenting here to
there demonstrate you guys what can be
done good what cannot be done inside
programs and all foreign programs and
all okay now
possibly now this module is on top of
the program so without the keyword
contains so let me run this that means
let me compile this
still another still errors are popping
up okay maybe I should be used over
keyword contains contains should this I
think they should avoid error but it
does not okay let me okay it does not
okay
now on the other hand on the other hand
let me remove this use underscore hello
one and run this still showing another
okay on the other hand if this being the
case then we do notice something over
here and here
subroutines and in a programs and
subroutines and functions can be can be
inside them you're using
key word contains using keyword contents
fair enough
module now we notice that not at all not
at all not at all so you cannot define a
module with inside a program since I
mean inside the definition of a program
but outside let's see
but outside okay let me just cut this
out let me just cut this out and if I
were to I write this at the bottom if I
were to compile this
it is showing me that the this is
showing me some issues over here
okay saying something like subroutine is
not available and something of that sort
module is here by the subroutine is not
available something of the chart okay
maybe this implicit none and contains
are not there
okay then were to still run this it's me
that errors are gone but it's showing an
error that use hello one the this mod
there's a fat layer because this module
is not available okay now let me write
this on top of the function let me write
on top of this function sorry the top of
the program hopefully this should work
okay
I compile this it works properly I run
this we need to build is fine could run
this yeah it works fine so what what
does this mean well so let's answer this
question here can a module be placed
inside the script inside the program not
at all
out outside the program or see the
program yes okay on top of the program
yes our pillow the program okay below
the program no no okay
in new file a new file yes but this file
to be compiled first this file has to be
compiled first so inside a program you
can use subroutines and functions inside
the function or outside in a Cell
outside or in a separate file no problem
okay now as for us okay now this is
something we have to keep in mind this
is something you have to keep in mind
okay now I will pause the video and I
like I'll pause the video and I will be
back with with the mean function
definition and the subroutine stuff
subroutine definitions separately okay
now I'll be passing the video here okay
guys coming back what he did is that
here we just looked at the program now
what i did i just wrote a new file
called as demo 1 dot F 95 and this is
this I mean this file what I have is
that I just have a big integer function
right from the top to the bottom over
here and this function has an intent
value in out value namely X ok even if
it's indices doesn't matter over here
since it's in doubt I'm getting the
value X I can modify it inside the
function inside the function and then
I'm printing it and then I'm setting
that F 1
equals x FN equals x nothing more and
now this value gets returned
whenever the function gets called now
the most important thing is that ok can
and in function contain another function
inside it another subroutine inside it
okay that's something you have to keep
in mind no it is that part now is that
possible is that possible
now let's see it lets see it for
ourselves now you have a real function
inside here and a subroutine inside here
if I were to compile this
it doesn't throw me nearer even if I
build this it will throw an error
because there's no main function to
compare I mean there is no main function
the main program and something to work
with so you but it when you compile this
it works fine so it so what you can
infer from here this simple functions
and subroutines can be fine his
abilities inside them yes yes it is
possible
but now the program no say let's see a
program ok now let's check this out can
I program the inside contains ok they
already have a condition the top program
new world program ok
nothing much implicit man
trend star hello a very minimal program
ok for the run this it will throw an
error ok because inside the inside a
function you cannot have a program you
know this might be rude so this is not
at all this is not at all you cannot
have a program inside a function or a
subroutine ok ok now this flow in this
program we saw that do you have a module
ready so if I were to compile this
it's fine now can I use a module here
inside
okay can I use that it's is that
possible over here let's see now I just
comment this out because you cannot have
a program inside function so but can I
use a module inside yes it does but how
you have to use the use command to have
the Fortran to have the module functions
and definitions praten so a program not
a dog other modules functions
subroutines
yes yes use the use module statement
okay
simple fine and one more thing sure can
I have a module inside
let's see module add me a litigate one
module new world implicit none contains
okay subroutine h1 which contains which
has implicit none and print hello let me
comment this out at the end
so what am i typing subroutine h1 okay
not with that I'm ending the module here
ending the module here if I were to run
this it's an error because a subroutine
so because a function cannot have a
module inside it okay that's something
important a function cannot have a
module inside it okay so let me write
this down a module and a program and
module not at all so we say we found
that inside a function you cannot have
you cannot define you cannot differ you
you cannot put you can you can I mean
inside a function you cannot put inside
a function a subroutine you cannot have
a program or a module inside but you can
use my other module function using the
used module set in command okay and
finally one more stuff the more inside a
module can have functions and
subroutines inside them yes of course
yes absolutely because that is out
whether it is how a module is designed
okay
now here's one more thing I can since
here's one more thing can I use modules
can I use the other functions and
subroutines inside for this module let's
see a program let me take the program
inside inside a module can i I think
it's not possible not possible okay the
modules other modules functions
Russy functions and sub functions and
subroutines yes other module functions
are proteins yes it is possible
how use the let me copy this feeling a
little reducing we're being a little
sauce we'll hear you use the used module
statement simple as that
okay another another module inside
module inside of module let's check it
out okay
for this I'll be passing the video I'll
just write a short module let's see
whether this works or not
no I don't want to pass let's do this
okay let me make this a module itself
module sample okay
implicit none okay
contains okay and here I write okay
sample okay favored to run this the way
it have a have another because you
cannot write a module inside this so let
me just you know comment this out okay
sorry comment this out okay so what we
saw is that inside inside a function you
can define a function and the subroutine
so I think this also goes well for a
subroutine inside a subroutine you can
define other functions and subroutines
but it is but you cannot define a
program inside a function so I believe
that the same goes what possibility and
you cannot define another program inside
a subroutine okay okay now because of
this this module that will not work now
is how to compile this in a more inside
a module you can have functions no
problem you can have functions and
subroutines no problem that's that's why
it what modules was defined now can I
have sorry can I have another module
inside it
again is it possible never to uncomment
the lines I'm proud of this no you
cannot
so it says that inside a module it
cannot have another module so he'd say
other model inside of module sorry
it's no it cannot so that's all I have
for you guys understood if you guys
notice yeah sorry sorry my bad anyway
so this is something you have to keep in
mind because this I mean a many of the
tutorials and stuff you might be
wondering whether you can put this in
put this not or not I have to experiment
this but for newbies and other people
who other people for newbies this will
be really good but for people who are
but for people who wanted to know write
a very very complicated project and
stuff like who wants to you know copy
files from copy contents from one module
to other use functions from one muslins
or other module and something of that
sort we want to build functions inside
other functions the modules inside other
modules like somebody's there's other
separates and something of that sort and
if you want to use those kind of stuff
okay then then this is a quick
introduction interview for all of you
guys so this by this example you guys
understood the what what what can be
done and what cannot be done what can be
done and what cannot be done sorry let
me comment this I can be done and what
cannot be done by merging one thing into
the other at all okay now if I were to
compile this it works fine so so this is
in summary of what we did today or in
the in this tutorial the subroutines and
functions can be built inside the
program can be written inside the
program using the keyword contains
outside the program and outside is
always the program yes it is yes it is
can be done but in a separate file yes
as modules are a separate files but
those
those files has to be compiled to get
the object files ready to bring them up
okay but can amaz will be placed inside
a program not a talk we rechecked it
very clearly that it cannot do it okay
now outside the program yes a model can
be placed but on top of a program yes
but below a program not at all but in a
new separate file yes but what happens
is that when that is done then now the
entire module has to be compiled first
before comparing the program okay and in
regarding functions regarding functions
and subroutines sub functions and
subroutines can have can have internal
functions and subroutines so it does
work but a program and the functions and
subroutines cannot have a program and a
module inside them but other modules
functions and other sub subroutines can
be used inside them using use inside I'm
using the used module statement use
module statement and so and finally
inside a module by default you can put
you can define functions and subroutines
using keyword contains yes using--
contains using contains but in but
inside a module you cannot have a
forward you cannot have a program inside
of module it's not possible but you can
you have canny how can we have the
functions and subroutines of other
modules modules put inside yes it is
possible we have to use a use module
statement that we saw previously and
finally can you have a module inside a
module something like a inner module in
your module something no not at all so
this might this is something you have to
keep in mind when we go for the people
wanted to go for advanced procedures
advanced procedures were and people want
to work with one program inside other
one subroutines are other or something
of that sort that's all I have for you
guys in this tutorial thank you guys for
watching and see you guys next tutorial
bye