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So today we are going to talk about arithmetic operators, so we've gone over the logical operators.

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Now it's time to talk about some of the operators that have a little bit more to do with standard math,

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things like addition multiplication division, stuff like that.

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And we'll notice there's actually some, some more operators besides just those standard ones that I've

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just mentioned.

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So I went ahead and took the liberty of making a new file here called arithmetic operators to keep you

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notice.

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I'm quite lazy and I'm still putting it in this first program directory.

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But of course, it's a good idea for you to organize your files in a way that is easy for you to go

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back and look up things for reference.

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So I just put it in here, but you can make it wherever you want.

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I also went ahead and pulled up another terminal.

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I'm doing it in Visual Studio, so you can see again today.

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So you can just pull the terminal up as well so we can go ahead and compile and run our stuff.

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I have already made a main function in the skeleton with some comments, and you might be wondering,

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Hmm, I haven't seen this before.

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Up here.

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What's with this?

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So I'm just going to kind of sprinkle in some random things to the lectures that aren't having their

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own dedicated topics.

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You noticed that I already mentioned something about comments you might have seen that mentioned in

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other videos as well, but we talked about a comment on a single line, which is a slash slash before

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it.

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This is the same thing, except it's a multiple line comment.

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So it's kind of nice sometimes to put a description for your entire program at the top.

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Or if you needed to describe another big chunk of code, you might want to put a block comment, which

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is something else.

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You can call this or a multi-line comment.

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The way to do that is to put a slash and then a star to open the comment.

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Then you can type as many lines as you'd like and you close it with a star and then a slash so you could

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add more lines if you hear if you wanted to another line.

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You know this if I get rid of this, you notice it just goes all the way down to here.

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It sees this star slash that they put right here, and it considers these comments just because they

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have slash slash is already in front of them.

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So you got to make sure to close it.

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But yeah, just something else I wanted to mention.

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So you don't have to have these on a new line, either.

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I can back this up right on the same line.

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I can also work this out right here.

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You can put it like that.

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However, you would like it to look as long as there is an open slash star and a closed star slash.

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OK, so pretty cool.

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You know, I'm also including, I assume, because of course, we're going to be using that as always

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to print out stuff today.

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I'm going to go ahead and not do the using namespace skinny thing.

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I'm actually going to use the study for the standard namespace in the colon colon scope resolution operator

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to put before see out and before in line.

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Just because I'm going to mix it up, we'll be using it sometimes or sometimes not be using it.

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Like I said, I don't think it's like a horrible thing to use it, like you should never use it ever.

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You know, it's put there for a reason, it's possible to do it for a reason, so, you know, maybe

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not a good reason, but you can use it if you don't have to worry about some near-space collisions,

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that's something we'll get into later.

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But it's good programming practice to not use it and instead do this, which you just have to put this

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before anything that you would use inside of extreme.

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Something extreme is coming from the standard template library and C++, so it gives us access to things

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like see out and in.

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And so the difference is is you're going to see this.

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Rather than just this, and you will see this rather than just this.

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That's the only difference today, at least.

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OK, so with that, let's go ahead and get started.

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Make sure you have a main function here with the brackets.

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And then I have a lot of comments in here that just talk about what we're going to get into and discuss.

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So first off list, declare some variables.

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I'm going to leave this up to you.

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So why don't you pause the video and come up with an integer of float and a double variable?

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So hopefully you went ahead did that.

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I want you to get some practice and remember how to do that because we have discussed that already.

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So if you're still a little wobbly, you can go ahead and just do something like this.

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But whatever value you want, I'm just going to say this is five an integer called i1 that has the value.

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Five.

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I'm going to say a float and I'll call this f one equals ten point five, and I'm going to say a double

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b one.

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And I want to say this is fifteen point twenty five.

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Cool.

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So now we have some variables.

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So the first thing that we're going to go over is the basic operators.

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So these are things that you've probably seen before in math, this asterisk here is for multiplication.

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This plus is for addition, the minus is for subtraction.

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The slash is for division.

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And this you may or may not have seen you.

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Some of you might know this as the percentage sign, but it also has in programming.

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We refer to it as the modulo or modulus.

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So this just means remainder, and you might have already used modulo or modulus in mathematics.

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If you've taken a math class that deals with that stuff, maybe like discrete math or a number theory

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or something like that.

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But if you haven't, don't worry, I will explain what its purpose is and how to use it.

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So with that, let's go ahead and print out some mathematical things, like some operations.

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So I'm going to do ask Colin and call Remember and then ask out and I'm going to do.

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Let's just do something simple, so I'm going to do I one.

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That's our variable that has the integer five.

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And I'm going to do.

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Plus I won.

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Actually, I do have Class One to call, and then here I'm going to do an SUV and in line.

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So let's go ahead and print this out before we do that.

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Tell me what you think this result is going to be.

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Of course, I can't hear you say that, but just think about what it would be on your own before it

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gets printed out.

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So I'm going to save this and I'm going to actually meet all the D Plus plus I, so I'm in the directory.

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If you need a change to your directory, go ahead and change to the directory that has your file in

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it.

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That would just be.

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Make sure to follow this path up here.

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So I'm going to do G-force plus arithmetic operations to repeat that, oh, to name this swimmer, to

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name my alpha file and I'm going to call this just areas that you see.

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OK, now I can run it, so I'm going to do that slash Anthony ACSI.

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And we see in 11 here, so what happened was we had a I one was five plus one is five, so that's 10.

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And then we added one to that, which gave us 11.

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So that's why 11 printed out.

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So it actually printed out the result of all this.

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Cool.

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So let's try something else.

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We'll do another line this time we'll do some multiplication, so why don't we do F1 times to

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put that SUV phone call in?

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And so, yeah, let's go ahead and save this and run it.

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So I'm going to compile this and run it.

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And we noticed that we get twenty one, so this is a ten point five times too.

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So, you know, ten times to twenty point five times two is one.

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We have twenty one here for our result.

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Let's go ahead and do some divisions.

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So this time I'm actually going to throw in some

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parentheses just for the heck of it.

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So remember, the parentheses are things that you can actually use to separate a lot of stuff.

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So in math, you might have used like parentheses when you talked about the order of operations, which

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is what we will do next.

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We'll talk about the.

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Operator precedence, which is order of operations, but you and Matthew can sometimes separate things

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with parentheses, right?

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If you want something to happen first before something else happens.

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So I'm going to do that just right now, kind of.

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It's a little like precursor to us going over the order of operations.

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So I'll do when I want times to.

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So that is going to be five times too, right?

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Because five store in here.

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So that'll give us 10.

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And then here I'm just going to say divided by five.

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So that'll happen afterwards.

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And you don't have to put spaces here if you want.

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You can just go like this and put them right up against each other, I like to put spaces just to make

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them look nice, but you know, I'll go ahead and leave that with no spaces just to show you.

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So I went ahead and saved it.

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I'm going to go ahead and compile it and run it.

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So we didn't see we get to here.

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So what happened was we did five times two, which was 10, and then we did 10, divided by five, which

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was two.

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Cool, so pretty interesting.

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You know, we can actually, like, add some stuff in here like I could do a minus one and compile this

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and run it, and then that becomes a one because it subtracts the ones that's using the subtraction

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operator.

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Let's look at this interesting one, though.

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The modulus.

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So I'm going to do

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another.

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Let's see.

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I just choose.

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I want.

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Actually, I want is five.

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So I will do I one one two.

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So what this is going to do is it's actually going to get the remainder of the division by two.

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So when I say division by two, I'm talking about five divided by two because I want to has five, right?

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So five divided by two.

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Two only goes into five two times.

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And there is a remainder of one left right, because two times two is four.

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That's that's one less than five, there's a remainder of one.

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So let's let me kind of be more concrete about this, too.

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This has there's a little bit of a nuance with the division, too, so I should point that out first.

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Actually, the division is depending on what you have over here.

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So if I do, I one divided by two.

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Let's see what prints out, actually.

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So I'm going to go ahead and say this and run this.

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OK.

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So you notice that only two prints out, but five divided by two is not to what it's doing is it's actually

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just rounding it down.

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So it's just saying OK to the integer two goes into five two times and it gives you an integer result.

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But what if I was to go like this and put it two point o instead?

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So now it's not an integer type that I'm dividing it by looks.

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It is a floating point, kind of, you know, like this float double.

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So let's go ahead and save this, and then I go down here, compile and run it.

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So you notice now it says two point five, which is actually accurate.

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The more accurate, you know, five divided by two is actually two point five.

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So if you add a floating point here on the right side of the operator, so you have a floating point

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upper end that will give you a floating point result here.

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But if I just have the two, then it just kind of rounds it to two, even though there's that one left

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over right.

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We talked about the remainder of one.

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So what happens if I put the modulus, then let's go ahead and run it.

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So it actually says one.

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OK.

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And it does that because there is one left over like we talked about two times.

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You know, it goes in two times and two times two is four and five minutes for one, there's one left

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over from that modulus.

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There's something really interesting.

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It's actually used a lot in computer science, as we'll see later in the course.

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It can have much broader applications, so really cool, operate a really cool concept.

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All right, so that's kind of all I have to say about these basic operators.

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Let's go ahead and move on to like using more parentheses and talking about the precedence between operators.

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So I'm actually going to comment this out for now.

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So what we can do when I say commenting out, we're just going to transform these lines into a comment

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by putting the flags in front of it.

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So.

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Like this list now, they're considered comments, so this code is not going to run anymore because

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it has to slash last before it's seen as just some comment, just like this one.

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So you can uncomment them if you want to run them, but I'm going to count them out just so we can have

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kind of a clear, concise output here.

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So let's go ahead and use our variables again.

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But what we're going to do now is discuss the order of operations or operator precedent.

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So we have this multiplication is the first.

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Then after that comes division and then we have the modulo and then we have plus and then we have minus

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here.

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So that's kind of the order of operations, if you have heard of that in math and some other math class,

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you know that there was an order to things like you maybe have heard of him dos, which was like starting

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with the parents parentheses, the parentheses, exponents, multiplication division, addition, subtraction.

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That's what that acronym stood for.

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So in code, we just call it operator precedence, and it's really the same thing.

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So if I knew another line here, I'm just going to copy this

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cool.

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So let me go ahead and.

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Modify this a little bit, so let's think about and think about this, so if I want to do something

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like I'm one plus two times three minus one.

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So let's go ahead and save this and compile it and print it out.

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So we have 10 here, so I want us five, right?

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So we have five plus two times, three minus one.

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Well, you know, what's actually happening is this first, so we are two times three, which is six.

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And then what it's doing is it's saying, Oh, OK, we do this first three times two six, six plus

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five is what it'll do because of the order, other operations, which is 11.

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And so this is 11.

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And then it does a minus one, which is 10.

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So what if we didn't want it?

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What if we wanted to just have it in left or right or, well, then we'd have to use parentheses, right?

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So sometimes it's good to use parentheses if you want to force some some sort of mathematical ordering.

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So right now, we expect it to do five plus two.

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So there'd be five, six seven, we'll have seven times three then, which will happen next because

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multiplication happens before subtraction, seven times three is twenty one.

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And then we'll have a minus one.

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So we should we should get the result of 20.

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So I say this, compile it, run it and we get a result of 20 like expected.

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So that's kind of just, you know, what's going on with precedence here.

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If you want to, you know, if you wanted to flip this around, let's say we did a minus three times,

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maybe like two or something like that.

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You know, what it's going to do is it actually is going to evaluate three times to first and then it's

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just going to subtract that from this.

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So if you want this to happen all in the same order, really what you're going to need to do like in

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left to right, what are you going to need this surround this in parentheses as well?

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So that is something that you can use as these parentheses to force the ordering, otherwise that happens

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in this order here.