Fortran Programming Tutorials (Revised) : 012 : Relational and Logical Operators Video Lecture | Introduction to Fortran Programming (Basic Level) - Database Management

hello guys my name is Aaron and welcome
to my channel this series is a series of
tutorials on Fortran programming now in
the last tutorial we saw some we saw an
explanation to an if statement and
relation large relation logical
operators and we finally finished that
program wherein we were to find the
distance of a certain point from the
origin the angle that line the angle the
line that connects this point and the
origin and also the the quadrant in
which that point is lying using the if
statement and law okay
and during that process we used
intrinsic functions which I have
explained to you guys about parameter
and some features that are in geni and
how to execute programs from geni my
simple ones okay now in this tutorial I
thought of concentrating on
concentrating on explaining you guys
about relate achill I mean sorry
relational and logical operators and and
to start with what I did is that I just
wrote a simple program I mean I haven't
having to tie this outer skeleton of our
program that we wanted to work at this
program will demonstrate in this program
we'll write a demonstration to explain
how the logical and related relational
operators behave okay so the program
name is relation in the Skoll logic dot
F 95 sorry that's a file name the
program is rel and the score logic and
it starts here and ends here what did it
is that I just copied some I just copied
some I know the instructions I've made
in the one of the previous programs to
start give a give a little head start
okay now I feel that it's more than
explaining guys it's better I give you
guys a little hands-on hands-on idea
what it means what is logical operators
are okay
so these six are actually relational
operators meaning they compare two
objects they compare two objects or two
statements or two variables or two
expressions and say method and say
something about it like whether they are
greater than or rather than greater than
or equal to or completely different or
something so the relational operators
that are available of Fortran are d6 the
first sim the first symbol a double
equal to
which can also be written as with a dart
EQ and another dot okay is the equal to
operator meaning it will compare and to
object when two objects are two
statements or two variables so extreme
completely equal or not and when they
are equal it will return it return a
logical answer say true or false
similarly this operator is the greater
than operator this is the less than
operator this is the greater than or
equal to this is less than or equal to
and this is the not equal to operator
these vary these operators go very much
similar to the mathematical operations
we use mathematical relation operators
we use okay and then what we and then we
already have other logical operators see
logical values higher on can have only
two two answers either it can be a true
or a waiver false sometimes they call it
binary yes I need one and zero or a yes
or no but in Fortran the logical
operation implemented as true or false
okay
and this true has a dart in front of the
other bag just like these operations
over here okay and there are five file
logical operations available and not
logical operator and operation or
operation equivalent operation not equal
to not not equivalent operation now I
will explain you guys how this works and
I already explained already wrote the
how or not not operator works what it
does is if they have a logical operator
or logical statement okay and what not
does it just gives the compliment of it
suppose your value is one we will give
us 0 suppose your value is 0 it will
give us false it will give us true so
just for a reminder in my notation okay
let's assume 0 to be you know let's say
let's take you know as actually true and
false but I wrote 1 and 0 so that you
know you can try finishes you can write
you can just write a little is simply ok
zero means false in the in the notation
we are using here and 1 means true ok ok
that's clear now what what
I was writing a program so that may fill
this table it is here to explain about
on how and are equal not equal and
operate equivalent or not equal and
operator works people might call this a
little with a different name but let's
see how it works
okay to make this work I thought of
let's go with a few operations variables
like normal slot in values integers
integers I just need two integers a and
B okay and logical values let's see
yum come up in okay I'll use the print
statements to define the values okay now
a equals one it's a equals 4 and B
equals sign to start with and then I
define the logical value m to be true
and n to be false
okay now let's go with the relational
operators because that's a little easy
to finish I just using a print statement
print yay equal to be a equal to B and I
type a equal to equal to B okay equal to
equal to B and I just copy this copy
paste it here see if you guys want to
know repeat the line that you guys made
in genie why I do is put the curse put
the cursor anywhere in the line and
press control D it will just replicate
the line that you are is presently in in
the next line and then if this is next
body how is a greater than B okay let me
just make it here and then I repeat that
now it's this is now less than B and I
put that less than operator here at this
control D now it's greater than or equal
to now this is greater than or equal to
control D less than or equal to less
than or equal to and control D finally
not equal to know what I supposed to get
is that I should get to one Falls
accordingly now for the values of a and
B now to print a and B okay just I'm
just typing this a equals come I a and
space B equals B okay simple enough
that's hot just these we're just using
print statement to get the answers okay
lets me compile this okay it just gives
now it gives no issues okay now build
this okay f8 and f9 and then when I run
this yeah we get dancer a equals four B
equals Phi now is aid equal to it is egg
equal to B false we are getting a false
answer they're getting a false okay now
if you see a greater than B no because a
is 4 and B is Phi so a is not greater
than B so we're getting a false you see
a less than B true yes yes it is so we
are getting and we are getting a true
is he a less than or equal to B false
because you see a greater than equal to
B false so we're getting a false F
symbol and if it is a less than or equal
to be true so we get a true is a not
equal to B true fine now let's change
the values and work this out pi and four
okay
now I compile this run the compile this
business and run this yeah now if you
guys notice the valley flips if a equal
to equal to B no so it's false that's
true a not equal to B true it's fine but
these changes a greater than B yes it is
so it's true a less than B it's false so
it's far F and similarly a greater than
equal to B true a less than or equal to
B false now
instead of just these variables I can
show these variables like a new
statements and compare them also and now
if I want so that's that's how this goes
and then let's go with the relational
operators let's go with it we'll go with
the relational operators to see how they
work with now initially I said the board
to be I mean let me set them both to be
false
okay let me set the board to be false
now print star equals yum equals come
young okay and then space yin the yang
equals come again okay now no print star
comma M it not M equals and not sorry
it's a naught M okay and trend next the
next item I comparisons will fit the
table here
come let me know you know what I just
copy this copy this and paste them here
let me just make the corrections simple
this might be a little easy yam or a say
yeah Morin it's our statement here this
is actually the our statement that we're
using so it's m dot or dot N and then M
and
yen okay and this is young dot and dot
yen okay and this is M eq v dot and then
and this is m dot e QV it's eq v dot and
we'll remove this symbol off and this is
in and finally m n eq v en and this is
yeah not an eq v dot yeah okay now let
let the let's get this printed so before
to make sure that edison to do not do
not get you know plastered let's comment
out this right click format and comment
lines let's comment all this so that
these does not get interfere we now with
these values let's fill these tables up
now come pie I haven't used B at all
yeah that's okay
no you just come on this out - no
problem no compilation errors no
building others run this yeah they
result the same now
m-miss we said um to be false and end in
to befoul so we get these this was to be
false
now if you guys notice yeah M is said to
be false so not of M is actually true
because it returns the opposite okay and
then vm r en what it does is it sees
whether both of them are true or what
them are false if both of them are false
it sets it gives false if one of them is
true he gives true if both of them are
true it gives true so and in a.m. and
then if both if you'll check swore it's
X what's common between these two okay
if both of them are
fast it returns false if one of them is
false it returns false but if both of
them are true it returns true okay
now this being said we'll come to this
equal and not equal and dynamic in a
minute okay we'll come to the equal and
unequal in a minute it's a that's a
little tricky so what and does is if
both of them are if both of them are
false
you'll return false as if one of them is
false again will return false okay now
only when both of them are true it
returns true so this is how the table
goes by you guys can you know play with
the values of M and n I mean I'll play
with the values of M and an experiment
with it and you'll get the same what our
does is if both of them are false return
false that is if one of them is true it
will turn true but if both of them are
true he'll again return true fine okay
now let's see how if this equal and
symbol looks like ol + symbol looks like
for that let me not you know include
these into the picture so that our
results do not get messy compare build
and execute yeah perfect now m-miss
Falls and n is false as we set here okay
yeah as we sit here so m equal and
Tenace true since both of the one of
them are false it's setting it's giving
a value true true then whereas M not
equal 1 to N is giving false so let's
set this this is true whereas this is
setting us to be false
this is setting us to be giving a giving
indication that it's false okay now
let's try for the remaining remaining
value let's n be true this time okay so
that we said this condition proper we
said this condition proper compile build
and execute now what do you guys see if
one of if M s Falls and yes n is true
and m equal to BN is false
where a semicolon to be honest
- it kind of flips the order so if this
being said this is 0 and this is 1 let
me just run this again yeah it says yes
it's the same similarly let's try let's
try this to be true and this to be false
okay compile build and run what we have
is that this equivalent operator is
saying that when when the first this
value is false and the other value is
true so what you have so this is false
so it's zero and this is this is true so
it's 1 and finally if you guys have a
look at it let's set both of them to be
true and fire let's find the final
result okay nicely compiled build and
execute yeah now if both of them are
true this is sending true wearing both
of them are far both of them are true
the not equal to operator settings false
so so to conclude this is 1 and this is
false so this is 0 you know represent
true or false you know in anyway so what
does equal and operated dresses you guys
compare look at the results if both the
results are same or of the same value if
both of them are false or both of them
are true he dresses her it results a
true operation whereas if the 1 any one
of them is false
anyone both of them are different there
it it returns first the exact opposite
is done by in n equal table n equal
operator what did the says n equal in
eqv operator what it does is if both of
both of them are the same then it
transforms
if you saw if both of them are different
then it it runs a true value so that's
all I have for you guys in this tutorial
and this is our relation operators and
logical operators work and this our
logical operations can be done
and if you guys know that this is not
this is not the only limit you can use
this operations in several several
different varieties especially during
comparisons and for checking constraints
or taking certain conditions are coming
or not for in sub programs like you know
if you have some certain programs like
you know trying to find the date of a
year or trying to find whether a month
is early whether a month has to 30 days
or 28 days or 30 days or whether a fine
whether to find the year has you know it
sleepier or not those kind of conditions
logical operators and relational
operators are very helpful and these
from the basic decision these are very
helpful for making decisions as far as a
program as far as a program goes by and
that's all I have for you guys in this
tutorial thank you guys for watching and
see you guys the next video bye