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So will come back again in this lesson we're going to talk about functions in swift which are a rather

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important topic and although they're quite important they're actually very simple to use in swithe so

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I'm going to quickly show you what they are and what they mean.

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Let's go to Scott.

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And this time I'm actually going to go and make a project.

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So once you put an eye in here and my quest command line tool if you make sure it is this language is

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free.

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And when I call it functions even if it's true.

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OK.

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And now create.

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So functions like strafed are in terms of the principles are exactly the same thing as Objective-C and

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most other programming languages they offer us a way of modular rising or code that also offer us a

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way to call a same piece of multiple times.

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And they help us categorize our code.

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So imagine I want to make a function in the past if this was objective c we would do something like

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this.

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We would do with Dasch depending on whether it is a constructor or not.

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And then we would say return type and then you would say name of function and then we would say a column

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and then we would say argument type and then would say a man's name.

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And then this whole thing would continue would have multiple arguments more human type so on and so

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forth.

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In swift It's actually a lot more streamlined.

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It is very much like most modern programming languages.

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So here is how I make a function that doesn't have any arguments doesn't return any arguments.

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So I'm going to say fine.

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My function doesn't have any arguments doesn't return anything.

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And here is the body of my function.

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If your function doesn't return anything that's kind of like your void function so it would actually

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either void in here if you want to.

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Well you can just completely drop it so this function whenever it is called It just does something such

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as What if I saved print hello and then somebody in here call my function that would print hello for

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me.

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Let's see that in practice

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that says hello and something you probably already noticed is not on like objective see that we had

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to say sell for and then self name of function and then bracket.

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In Shreeves we just call the name of the function with its arguments.

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In this case there are no arguments.

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This is of course giving an error simply because it's Objective-C.

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It doesn't work in here.

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So removed that.

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How about we now add an argument for a function.

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How about we are an argument that receives a name and says hello data name.

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So I'm going to go in here and say well I have something called input's name of that type of string.

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So my function has an input name of the type of string and whenever you want to print to say hello and

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then we interpret it in name.

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So whatever input name we have got them we say hello is space plane.

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So they call a function like this.

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I would simply say my function and data you have to enter name name.

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I'm going to say that E-Myth name is a war that's wrong not

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perfect it says hello worth.

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Hello comes from within the body of the function.

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The word comes from the argument.

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Now what if I had multiple arguments with you then just have the implant.

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Well what if my heart in name and the last name of that type of string.

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Well it would be exactly the same thing it would be hello Whatever say is space and then another one

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eem last name and then in you know I had to actually enter the other piece as well.

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And I would say hello ward.

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I don't know that's a weird last name to make right now.

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Hello world.

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All of us are good.

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I got there.

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OK.

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So hello we're off I was on the air with preens.

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Hello world.

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I was so so far we had a function that receives some argument or it can do whatever you can imagine

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between them and give us a response.

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For instance if you give a function that is going to multiply two numbers you would simply be lets say

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Im OK so if my fine shin and then I would say Im a of the type integer and Im B of the type Integer.

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And then I would say do this lets the rest of the Im a multiply by Gimple B and then say print and in

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the print say raise e is and then I would do one of these.

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What is raise raise is this.

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And then if I wanted to call that function I would say my function and it says hey you have to give

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me one guy called him put eight of the type integer and other guy of the type you know integer by the

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name of input B.

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I'm going to say 5 by 17 so far is five by 1785 I know top 5 y.

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So it's fun.

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It is right.

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Yes it is.

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I felt like second I doubted myself.

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So yes.

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So that's how we call a function that has multiple arguments does the same something.

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And then once it does that thing it you know it doesn't return anything the return is still void.

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So what if we wanted to actually get the return.

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What if it didn't want this guy to preens there is rather than that we wanted to see the actual raise.

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So here's how you would do that.

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I would say well this guy now has a return type of integer and this return type of integer has to be

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returned the somber sort of return address.

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So once again I have a function two arguments as input one integer has to be the output Offut or outcome

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of this function and I'm going to say whatever you have to do mathematically or otherwise and then return

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that value.

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So essentially and this is a very important point.

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This goes to the core of programming if you're new to programming if you have done programming in the

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past you would know this very well.

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But if I was going to enter values such as two and five we know two by five becomes 10 right.

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So if I wanted to call my function here I would say my function and I would say values are 25.

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But then this is just like saying instead of my function in a middle of your code you have written 10.

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There is really no way that this thing is actually being used right now because it returns a value.

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So you have to do something with it.

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What could you do.

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I don't know you wanted to send it to be your registration for a user.

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You want to send it to find the value of the number of the other note listings that are associated with

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a certain user in a real estate application whatever it is you are trying to do.

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But you shouldn't just call it in here.

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The return is like numeric value because the return of the S would be 2 by 5 10.

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Is as if I wrote ten in the middle of my code which doesn't really make any sense what does make sense.

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Is thing this saying preens.

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And then in the print I would say let's call this function say that is what we want.

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So that would be a much more acceptable formula.

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It would be print whatever you find in here.

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And if I run this now it will give me 10 just like how we expected it to be 10 perfect.

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Or you could you know in here you could have a variable that is equal to that function.

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So when you're defining and declaring your function and you should have a clear plan for what is the

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arguments that you're entering into them and what are you getting from them.

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And why do they match there for whatever reason.

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For instance I could give you an example.

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Imagine your function was meant to remove the factors that you don't want.

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For instance you wanted to look at a string and he was like a clean string.

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So I would say this is an input string.

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And then the return is a string.

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And then in here I don't know how you would do this you would say that arrays a string would be empty

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at the beginning and then we would do some cleaning.

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And then we would have it here and read a string.

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So what is happening in here is that when we call our function in protesting of the type this thing

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of course when we call her a function and we give it this string it cleans it up and gives it back to

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us and then maybe just maybe if you remember from some of our previous lessons this was the string you

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wanted to pass to the next view controller for instance.

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So something like that would be would be you know acceptive or maybe you know you have a my colleague

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next the view controller.

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And the next few Kuntar has a receiver that dad thought that would become mine find shen.

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And then my function would have sent him first string.

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I'm writing this in a comment because this just doesn't make any sense.

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I don't have an X controller.

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This is just for the sake of demonstration essentially.

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So my impis dream would be like I don't know my text F.L. the text.

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So it is values that I don't know if they're clean or not.

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And I would send it to this my function he would do some Kooning he would return a good one clean one

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to me and I would push the clean one into the received data of my next controller or something to that

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effect.

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So so far we saw functions that they can accept arguments they can return values or they could have

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neither of those two.

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But what I wanted to have a function that returns more than one value.

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What if the situation that I had was this I wanted my function to receive value and let me know whether

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the value it has received whether it was a positive or negative value and also returned the positive

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version no matter what.

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So essentially here is what my function should do if I give it minus five.

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It has to get dive to me with five on a false saying the positive version of this is five.

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And it wasn't positive on its own.

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And if I gave it 17 it should give me like 17 and saying true.

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So I want some sort of a structure that allows me to return to more than one value.

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And that is something we saw recently in our previous lesson if I'm not wrong and that's it.

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So let's see how we could rewrite this entire thing.

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So fine.

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I mean that's our input input integer if is of the type Integer.

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And I have a return which is an integer and a boolean.

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Now let's see what you have to do.

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It's very simple.

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So if input integer was larger than minus one then I have to have a value card as boolean that's going

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to be by default.

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I'm going to say that to be true and then I'm going to say if it is larger than that.

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Don't do anything.

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So if it is smaller than zero Reza Boullion has to become false.

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That's one part of it.

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I also need the return value.

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So I'm going to save our arrays.

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Integer is by default going to be input in.

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And then if it is below zero gets rather integer multiplied by minus 1 so change its signature.

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Once you're done on through with that say return.

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What do I want to 10 or when I returned the AS INTEGER and I wanted a $10 billion.

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So imagine if a number such as 5 goes through this thing.

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It says that is five is smaller than zero.

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That's not happening.

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So 5 billion is going to be true.

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And as integer is going to be five.

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So let's test this out.

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I'm going to say I have a left my jeans being minus five minus five and I'm going to have to say I have

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a let.

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State is going to be.

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What is it going to be is going to be determine input value and the input value is going to be my in

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dots one the boolean one.

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So that's the state.

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And then let's pause number the positive value of.

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Here is the term.

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And then again does zero the zero.

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So I find the a state of faith if it is minus five.

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I find out the positive value of it was minus five it becomes five.

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If it is five days five then I would say print.

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And here's what I want to print.

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I want to say the number that they had which is my eant laws.

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What was it.

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It was the estate and is now let's find out what I know this that this earlier a very crude version

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of doing this thing but you understand the concept behind it.

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I hope so let's say let's see what you get.

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So if I wrong this is God tell me minus five was false and he's now five.

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And if it was 17 it says what does it say 17 was true and is now 17.

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Perfect.

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So again I managed to get two values out of a function.

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You could also call this one.

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You could call this one on the sign the number or whatever you'd like to.

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And then this phone call it a status.

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So just like two people that we could call its values or variables.

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You can also do it here.

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And if you had those you could essentially go in here and say well that one is that and this one is

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the stop this you don't need to rely on the indexes.

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You can't rely on the actual names and would perfectly work the way you expected.

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Before I finished this lesson I want to tell you one more thing about functions in swift which is again

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a unique thing to swift and that is functions that are nested inside each other.

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So I could have a function called Find the one that doesn't have any humans that have any return even

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though they don't really matter.

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And inside that I could have another function call it on nested one or anything that you want to call

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it.

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And then an inside one maybe does something for instance it says this is printed from inside.

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All right.

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So I have a function that is nested inside this one.

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And since it is nested inside function one I can actually say nested one or mess that find Let's call

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it Nesse that function so now I have a function which is nested inside another one and I can call it

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in here.

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It is primarily used if you have a very long function and for some reason parts of it they can be categorized

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but you don't want to expose them outside your function you only want to keep them inside to be very

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honest with you I don't really use this very often I can say that throughout the years maybe I've used

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it a handful of times so don't worry overly about you know what it is and how it works it's obviously

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best if if you learn everything and you know that they exist but you have to craft your own way of doing

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things and every once in awhile look up on line and look at other people's code and try to get a sense

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of you know how they are doing things if they're raised better now.

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We need a way to call these functions.

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And of course we can call this one because that one is not even accessible.

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We don't have access to that guy only.

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These guys have.

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So if we can call find one and if we do that and we run this code now it says this is printed from inside.

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So that's about not our.

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We talked about functions that they have no arguments.

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We talked about functions that they have some arguments we had we talked about functions that they had

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no return types they were voids or the ones that the vendor actually returning something.

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And of course if they're returning there has to be a return for them.

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Something has to come out.

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We talked about functions that they returned to post instead of single values they return multiple values.

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And if that's the case again we have written a similar id..

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The chance really you know ignore any of them and be fine.

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We talked about having nested functions.

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Here I have an error.

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And that's because of this.

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Because of that.

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And then in your argument I'm going to say Ninh I don't want you know in Arctic anything to it.

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So that's about that that's about functions.

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Let's move on to our next lesson.