Fortran Programming Tutorials (Revised): 022 : Select case and Calendar Trick Video Lecture | Introduction to Fortran Programming (Basic Level) - Database Management

hi guys my name is Aaron and welcome to
my channel this is a series of tutorials
on Fortran programming now in the last
few lectures we were looking at do loops
and in the last lecture I mentioned to
you guys as to how to you know compile
this F compile everything using the
terminal from genie now in this tutorial
we'll be looking at how to present
select case how to do select case
operation and it's one it's one of the
is one of the decision making statements
available and there's also a control
statement available in Fortran now
before we do that I I have already made
a prog already return a big program here
it's big program here I thought of you
know writing this as well I speak but it
was when I was recording this video it
was taking me some quite considerable
time you know explaining it and writing
it so I thought I'll just quote this
first and then explain you guys what's
going on to explain case select case
method here
I thought of devising a program okay a
funny interesting program that you guys
can actually learn something okay when I
was doing my high school and some time
before that okay I learnt a small neat
technique mathematic max technique
mathematical technique okay wherein you
can find any date you can find the day
of any date within the years 1991 to
2000 provided you get the year date and
month available now how do we do that
this is the logic here okay what you
have to do is that ask somebody that
yeah any year the last two last two
digit any year the month and the date
and we're using a small bit of
arithmetic here you can find the kak we
will find the answer for it I mean you
will find the day of it okay I just run
run run you I mean explain you guys how
this works I have compiled this and I
did build this it's working fine
if I just execute this program I give
you guys a demo okay
suppose I enter the 1996 okay
the Montes much as I go enter the three
because it's the third month from the
beginning of the earth and then I had
another date for so it's we are looking
at 4th of March 1996 and now if our
program is right you know what this is
how it'll show up it friends that the
year is 1996 the month is March the date
is 4 so the day is Monday if you don't
believe me whether it's Monday check
this out this is the calendar ok and now
let's go to March
let's go to March and then the year 1996
1996 and now if you look at 4:00 well ah
this is Monday so we are on this where
you are actually on my March 1996 and
March and the day is 4th and it the date
is 4th and it's falling on Monday pretty
cool isn't it now let's check this out
with some other date suppose we try 1957
ok December and since many of you since
let's take us a day that everybody can
think of let's say the first ok there's
number 25
it's a Christmas let's say let's take at
1957 the crystal 1957 is crystal
Christmas so it's December 25 1957 and
falls on awareness T let's check this
out here and now this should be a little
longer
October number this number and the year
is 1957 ok this has to go along
let's see there was a simple way to
leave forget about it
let's see the other system yeah let's
see there's a way to look at look this
is listen to me December 25 1957 857
okay if you just look at the date it's a
burn SD it's a it's a venice day 2 - day
again fine now we're looking at this a
program looks pretty fine okay yeah no
let me explain you guys has to how this
program works ok what do you do is that
ask a person's the person the year and
from that year define calculate the last
two digits of the year suppose if this
is 1996 ok the last two digits of the
year is 96 calculate that and then what
you have to do is that divide this and
divide this last two digits by 4 thereby
you get get an integer quotient you have
to do an integer division and divide
this last two digits by 4 and get an
answer save it separately
so here the way the 96 divided by 4 it
reminds it gives a quotient that's 24
now what you do is that based on the
month you have to find the secret code
for the month and for March that's
appalling ah 1996 the secret code is for
this score will be revealed as you go
along and then the date is for what do
you what do you have to do is then have
to sum up this last two digits of the
year the last two digits of the year
devil before the secret code m1 and the
date and find us to find the sum and
this sum is 128 for this example ok and
now what you have to do is that they
would take a modulus
the Sun with respect to 7:00 and get the
remainder and now and ligh based on this
reminder okay we will find the date
using another using an analgesic using
an another code that we will that I will
show you guys in a minute okay now this
is our program it's quite lengthy but
doesn't matter
we like Alex walk you guys through it
what do you do here is that we just give
the implicit down the variables here
here month and date one okay these get
third year month and date from the user
from the user
okay y1 as you use forget is used to
storing the last of the digits of the
year y 1 4 is this the Y weren't ever
before quotient
I mean integer division where 4y minus
for the storing the mod M 1 is used for
storing the secret code of the month
someone is actually first doing this
some and D is just for doing the modulus
operation with 7 and we and that's how
it this and then we introduce two
character arrays one for storing the
man's the other for strolling the days
this is only for you know the fact this
is only for fancy display nothing wrong
and the character character this
character string this string is there
are two strings here one a store for
storing the month and day is to use for
storing the day okay and then I am pick
I declared months here and I'm I gave
the name I stored the name of each month
of the year in the in the orderly manner
from the beginning and in the days here
I store the day with a name of each day
in these in this variable this string in
the string array in orderly fashion and
then using this print statement I give
explanation to the user to enter the
year month and date in order and then I
get that I read the read the year month
and date accordingly then what I do is
that I do this operation I do this
operation to get the last two digits
okay to get the last two digits what I
have to do since the number will be
always greater than 19 this code is
suitable with a 19 not 1/2 mm to get the
last two digits all you have to do sorry
yeah all I'll do is they take a modulus
operation of the year with 19 1900 1900
ok 1900 okay now this will give us the
last two digits and then why 1/4 we'll
do a course since all of them are
integers at the top why this line y 1/4
we'll get the quotient quotient by doing
the integer division of y1 with respect
of 4 and this is just to get this is
just a print statement I used to check
whether the calculation is going right
or wrong in the beginning but I just
counted out does it matter
now here comes a secret code finding M
as per this rule
this means a secret code and that secret
code result here is given here for if
the year is a non-leap air like 1995 or
2000 sorry 1963 or something like that
secret code is one four four zero two
five zero three six one four six each
value this is the secret code for each
month so for this for Padilla like 94
1994 or something just a not non-leap
year secret code for January's one a
code for February is for like the March
for March it is for by April it is zero
from 8 to 4 June 5 and so on similarly
this the year is an only if the year is
a leap year like 1996 2000 or 1992 then
this is the code we have it's just like
the book now here comes the interesting
part the Select case now I grabbed under
the entire program if statement using a
statement but to display to explain you
guys how select case works I've done
this all the decision-making everything
in select case I'll explain you guys
right now what salad case does is that
it needs a variable inside and
based on this variable case should must
take multiple values okay and the thing
is based on each and every value of each
and every possible value of the variable
certain action has to be the certain
actions have to be done so that being
the case so that being the case that's
what these select case comes helpful in
this criteria so looking at the secret
code suppose if the month is say suppose
if the year is a non-leap here if you
guys look at the secret code for all the
months from March to December except Jan
and February the the respective of
whether the year is a leap year and only
clear the codes are exactly the same so
what you have to do what I did is this
suppose if it's October it's October
then it's a tenth month of the year so
if it's if the case of month is ten then
I as a legate me I save the ie
denote the secret code for the month M 1
task 1 if the month is June sorry if the
month is March sorry me okay
the secret code is 2 so I allocate it
like this okay if the month is you know
August it's just the 8th month the
secret code is 3 so this way suppose if
the if the if you if I have like add
multiple statements here and all all
these statements will be executed if the
month is all these statements will be
executed if the month is you know month
the value of the month is 10 or if it's
an October that's it
suppose if the month value was 3 or 11
it means March or November then secret
code is for similarly they similarly we
go up to here here this way we cover
like 10 10 months now in this case now
here we delve into the the special
scenario of January and February
depending on whether
- nuclear or not so what they do is that
I am just working this for January first
okay
suppose in the month case now with the
month as it gets a value one that means
we are the user has entered January so
that being the case that being the case
we have we'd I introduced another in
Senate case within this select case okay
and this elet case I gave in a label to
it as Jan don't worry about this
underlined is just showing me a warning
that this kind of a case has cannot have
more than three more than two but it's
having three but doesn't matter it's how
doesn't matter okay in this other case I
made a I looked at a condition whether
if it if the modulus of the year is
equal to four zero one loss of the year
develop before this year is a repair or
not see if it's a leap year then the
reminder the modulus of the year with
respect to four will be zero now this
statement will return a true value or a
false value okay if it is true either if
the year is a leap year the January
should have a code zero the sake of
coverage january zero if it's a non-leap
error then the value should be the
secret code should be one so that being
the case i implemented here in the case
in the above case if the year is true
the case will be true so M 1 will be 0
and if it's false the year is not a leap
year it will be fast so M 1 will become
1 these are only two possibilities but
they no but you know
suppose the mean just in just in cases
that's this doesn't work this it doesn't
work out or something I just put a
default case where and you know if none
of these works what should be done if
none of these cases are true so that so
that that being said I know I wrote
default case valid I assign yeah moi am
going to be minus one I just gave a
statement stating that there's an error
in the year similarly for February I
just repeat this entire thing except
that the secret only the secret course
gets changed if we look at February the
seeker code for a February during leap
year history whereas
on non Libya is for so I just
implemented that here and the same case
default and the underlined is also
indicating that it's this it's this
answer will be logical so there will be
only two options and included three two
cases so I included three that's why I
just showing an underline it's a warning
but doesn't matter you know it's not a
big deal and then these two cases gets
her over with that end select since I
use the label since I use the label here
I get laid with this solid case with the
name John so I have to indicate to the
compiler that this error case is getting
here so I repeat the name John John
similarly is for this solid case I gave
a name I gave a label name called as Feb
so I have to indicate that this salad
key is ending here with the name Feb and
finally these two cases getting over the
default case then none of these fit none
of these 12 values fit I gave I gave I'm
giving a value m1 equals -1 I put it
printing printing that the it's giving
it's giving an error
it's gives us giving an error ok and
with that that's the last case and then
this you know they're all the possible
values of M have been used so I'm just
ending this up with sentence the 9 and
end select ok this is just I just wrote
this just to print how the manscape
printed this terminal but that doesn't
matter that doesn't matter
again I've used the same salad case
salad case for continuing the you know
see once this M has been done m1 says
everyone has been done whatever you do
is that the date is already known you
have to do the sum and then they have to
do the modulus and then you have to do
this do find the day and find the day
for which what I did is here is this
suppose if we end up with an error
somewhere here the value of M 1 will be
made will be negative so it's minus 1 so
that's why so what I did is that I eat
it with another select case with the
condition M 1 not equal to minus 1 now
you
this is not equal to minus 1 then it
what does it mean it means that nowhere
in the code that we not notice any error
with the year or the date so are in the
month okay
or in the month
so assuming that you know the user
enters the date properly we I mean I
didn't put any check statement for the
date you know it will just cost a little
more it'll be a little more longer court
but that doesn't matter here okay if
this is true I put this is this value is
true the case be the case would be true
and I execute the statement like if I I
find the sum and then I find I get a
divide I mean I take a modest operation
of this sum with respect to 7 and store
the reminder in this value in this
variable D and now based on this value
of D based on this value of D I passed
this value of D in this salad case and
for each and every value of this value
of D that you can choose I give seek I
give allocate mean I just save the
corresponding day for each value for
each value of B can choose okay I will
explain you guys what this means
suppose if if the reminder is grim
reminder is 0 then it's a Saturday
Saturday the first one it's a Sunday if
it's two it's a Monday if it's three
it's a - okay plus three it's a Tuesday
if it's four it's a red mistake it's pi
it's Thursday with six it's Friday it's
Friday now in this order were the first
in this string very string array the
first entry is Sunday and second is
Monday Tuesday Wednesday if this hour
so here the order is slightly different
so I'm allocating that if this reminder
turns out to be zero then this day will
be Sun Saturday which is actually a
seventh entry here so I wrote day equals
days of seven which is nothing but day
equal Saturday if they remain dressed
one it is a Monday and you get stored
here the reminders - it's a Sun it's a
Tuesday then if it's three it's Venice
day then it's for its thirst its its
fights for a sorry this is wellness day
sorry this is Tuesday when estate sorry
sorry this is Sunday sorry this is
Sunday this would be Monday the
statement will be Tuesday this statement
will be honesty this will be Thursday
this will be Friday and you know this is
not possible to have more than seven
values but in case you know test for a
precaution something it turns out of the
reminder is not zero or if it's more
than 7 or less than 7 or something we
just say we just print that there is an
days error and this error in the Sun and
then month will be the corresponding
month since then the value of the month
can be can't be somewhere between 1 and
12 1 and twirl the I allocate the month
accordingly suppose in a month if the
month
value well month is 4 then my end will
be for April if it is lemon the my
number and what I do is it I just print
them all I trend the year the month the
date and the day now this big this being
the case when this entire case is true
and if this case is false
ok this case is Fault III instead of
giving that as false I give it this
under the case default case okay if he
I'm gonna snow if m1 is indeed equal to
minus 1 there are some values that means
the in this error some values in the
there are some errors in the inputs we
just gave some wrong inputs so I just
print that and the program terminates
and that is how this this entire program
goes you know for since this is a single
program I can use this compile
execute to get the value okay any get
the value to compare this let me do this
let me compile this and business from
the terminal let me go to the location
as it is this is where the last program
was turned I created a folder named as
calendar trick this file is in the
folder name account the trick and if you
split LS I don't notice this gal that
trick executable and this on object
files and this is our file here I don't
want these two so I just deleted
sorry I just delete these two I just
have this to compile this key for tried
- see calorie calendar ok then click
enter nothing happens but it will be
execute it will be compiled and I will
have it an object for it this one now to
make this house an executable
what I do is G by G Fortran calendar
calendar click can't underscore trick
dot o and then I put this object - oh
flag to make to create an executable and
then I type Cal dot exe and I will be
getting I will be getting an executable
called as Cal dot exe instead of Cal dot
exe I can create another instead of exe
I can even create something called SP
PDF no it doesn't matter
this clay Curless ok it will also be an
executable you know just the way this is
just a notation but you know the I mean
the extension does not matter here
matter here and to run this what I do is
that I just typed Cal dot dot slash Cal
and type and what did I get the same
answer I like let me give a new value
this okay let's pick up a really cool
date in the field in the Internet
okay when was Pi Day first celebrated
March 14 let's see this March 14 is
actually the pi day okay let's see when
it got celebrated for the very with got
announced for the very first step okay
my Internet is a little slow here okay
there are two days actually pi pi day is
on March 14 okay the March 14 it's been
known from maybe 1988 it seems 1988 okay
the last case celebration of Pi Day was
organist by Larry Shaw 1988 okay so that
let's take this here and let's see when
did this when when does this for fell
into picture okay now so the year is
1988 the month is March day is 14 so my
14th of March 1988 is a Monday let's
check this out 14 March 1988 1988 what
happened
let's see what happened to this day it's
a month it's a Monday as per calculation
it's Monday perfect
now this is all I have for this tutor
this is all I have for this tutorial
hope you guys find it really interesting
and guys Lew check this out on other
people you know to check this out on
other people and I know you see a house
see how this works the only thing this
is the calculation turns out to be a
perfect this calculation turns out to be
perfect then your answers will be
correct do you guys make any arithmetic
if you guys make any mistake in that
doing the arithmetic then you might be
getting a little wrong answer but you
know once you guys correct it'll be fine
remember practice makes perfect well
that's all I have for this tutorial see
you guys in the next video and then
we'll go into
we'll go to one of the most important
topics of Fortran namely arrays we
looked at string arrays here that mean
the next topic will be looking at the
arrays regarding integers reals real
numbers and all which is the most of the
most important concept especially when
you're dealing with large large the
values of number numbers
so thank you guys for watching see you
guys in the next tutorial and most
importantly do subscribe ok thank you
guys