hey what’s going on everyone it’s your
bro here and in this video we’re going to cover some arithmetic in c-sharp
let’s get into it just a fair warning that this topic is
somewhat dry and boring but I’ll try my best to keep it fresh and interesting
there’s just some necessary stuff that we need to cover related to arithmetic
and you’ll want to learn this stuff if you ever plan on using any sort of math
in your programs which is like almost always the case for most programs so
arithmetic is the branch of mathematics dealing with the properties and
manipulation of numbers I didn’t come up with that definition I found it online
I’m not taking credit for it so let’s say that we have two variables and we
want to do something with those two variables integer variables let me
clarify so let’s say we have integer X and let’s give it a value of how about
10 and let’s create another variable how about y equals how about three alright
so these variables will behave as the number that’s contained within them just
like in middle school math class let’s say we have integer Z equals what we can
do is that we can say something such as X plus y equals Z and this will actually
work you can essentially like perform math on variable numbers because like I
said they’d behave as the numbers that’s contained within them
except if their strings and I’ll show you that in just a moment so let’s say
we want to print the result so console dot right or right line and then let’s
put Z in here and let’s see what happens let’s run the program so the result is
13 so you’ll want to be sure that you’re adding integers or doubles you actually
can’t do this with strings because they don’t necessarily behave as numbers so
let me show you so let’s say we have string X and string Y and Z will also be
a string now remember you need to put a string value in double quotes alright
let’s add these together and see what happens see what we ended up doing we
ended up with 103 it’s because these numbers are behaving as strings so what
we ended up doing was concatenating these strings together we appended the 3
onto the end of 10 and they’re behaving as strings and not numbers so you’ll
want to be sure that you if you want to work with a value and you
want it to behave as a integer or a double you have to give it the integer
or double type and not string so that’s why you can assign a number as a string
and it will still appear to be a number but it doesn’t behave as an integer or a
double so keep that in mind if you ever need to assign a value like a number to
a variable you want to be sure to get the correct data type integer or double
if you need to perform any math on it or you can convert it either one works all
right let’s run through a few of the basic arithmetic operators we have
addition coverage so subtraction take a wild guess 10 minus 3 is what you
guessed it 7 all right so multiplication you commonly see people to use like X
here if they need to multiply something in real life right well in programming
we actually use the asterisk symbol to multiply so 10 times 3 is you guessed it
30 all right next division you actually use
a forward slash for division so 10 divided by 3 should be what 3.3333 or 3
something right so let’s run this and pay attention to this we actually ended
up getting 3 and this is the reason when you divide an integer by another integer
it’s called integer division and it actually can’t store the decimal portion
of the answer so it ends up getting cut off it get gets truncated so if you need
to perform any division with integers 1 you can either just make these doubles
and you know that works and make sure the answer is a double two but one thing
that would be better is this concept called casting if you ever need to do
integer division so right next to the equation just put in the word double
within parenthesis and then you have to make sure the answer is a double the
variable or wherever you’re storing it okay so this will work then and the
decimal portion won’t get truncated done so here is our answer 3.3333
you know whatever all right so that’s one way you can perform integer division
without the decimal portion getting cut off
although you could just make these double values
that works as well likewise you can do the same thing with casting this as a
integer value so if you ever want to get rid of the decimal portion you could
always cast it as an int value so that’s one thing you can do if you ever need to
perform integer division all right let’s move on then so there’s this operator
called a modulus and what you do for a modulus is that you use the percent sign
so what this does is that it’ll divide this value by this value and the modulus
will give you the remainder if there is any remainder if we were to divide 10 by
3 3 goes into 10 what three times and we shouldn’t have a remainder of one then
so if we were to run this our remainder after using the modulus operator is one
then so this could be really useful if you need to determine if a number is
even or odd you could like divide a number by two and if it divides evenly
the modulus should be zero the result should be zero then if we
made this number so like a nine or something something that’s odd this will
give you a modulus of one so when we get to the video on if statements I’ll show
you how we can make a program to determine if a number is even or odd so
that’s one way that the modulus operator is useful it will give you the remainder
of any division I would say that’s enough for arithmetic operators for now
the next topic that we should cover is the order of operations in programming
so let’s say that you have a multi-part let’s say equation such as this two plus
three times four so what part of this do you resolve first you added two plus
three first and then multiply by four or do you multiply three by four first and
then add two well do you guys remember in middle school math class maybe it was
around middle school there is a an acronym it was PEMDAS and there was a
Aunt Sally although there might be some variations of that let me know in the
comments if there’s any others because I kind of want to hear
so based on that phrase on that acronym you resolve anything within parentheses
first then exponents multiplication division addition then subtraction in
that order well we have one for programming it’s a little more simple
you resolve anything within parenthesis first so if I were to put two plus three
in parenthesis here we would actually add a two plus three first and then
multiply by four so you can use parentheses to force operator precedents
in a multi-part equation such as this so if there are no parentheses what we end
up doing is resolving any multiplication or division first so that’s why we
resolved three times four first and then added two after instead of two plus
three first and then multiplying by four so it’s parentheses first followed by
any multiplication and division and then lastly we resolve any addition or
subtraction so before when we ran this we got 14 so if you want to change this
or force a certain part of this equation to resolve first you can force operator
precedents by just adding a set of parentheses so the answer should be 20
then if we have the parentheses because we resolve anything within parentheses
first and that’s all there really is to it to operate a precedence all right for
the last topic let’s clear out all of this and let’s clear out Z so in
programming we do a ton of counting we actually do so much counting that we
have our own shorthand ways of incrementing and decrementing values so
let’s create a new variable how about X and let’s set X to 0 now if you want to
increment this variable as if we’re counting what you’d normally do is type
in X or whatever variable you’re working with or value x equals x plus 1 so oh
then we have to display this alright so this is obviously going to be 1 right
all right so there’s a shorthand way of writing this because we’re lazy so if
you want the shorthand way of writing this just say the variable name then add
two plus signs and then a semicolon and this works just the same and it’s a lot
faster and what I mean it’s a lot faster I mean
a lot faster too right so that’s what you can do if you want to increment
something by one likewise if you want to decrement a value by one the longhand
way of writing that is something such as x equals x minus 1 and the answer here
would be negative 1 well what do you think we do here what you can do is just
type in X minus minus and this works the same all right so then you can also
count up or count down by a certain value so let’s say that we want to count
up by 2 the long hand way of writing that is x equals x plus 2 and the result
will be 2 now the shorthand way of writing this is that you can type in X
plus equals 2 semicolon and that’s a shorthand way of writing that same
equation there then if you want to subtract something by 2 you say X minus
equals 2 so these are called augmented assignment
operators I wouldn’t say they’re necessary but you might see them and
it’s just a shorthand way of writing certain equations if you just want like
a faster way of writing things well hopefully this video didn’t put you to
sleep it was a somewhat dry topic but that will conclude this lesson on using
arithmetic in c-sharp hey you if you enjoyed this lesson then you can help me
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