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Now is the time to start
working with functions.

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A function is a reusable
block of code that you can

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reuse later in your program
as many times as you want.

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So why do you need functions?

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Well, this will help you create
building blocks in your program

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that you can use and
reuse on top of each other

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so you can increase the
complexity of the application

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without increasing the
complexity of your code.

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Your code will stay
clean and easy to modify.

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And instead of giving you
many theoretical explanations,

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let's dive in and
write our first function.

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Okay, I'm going to remove all of that.

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And I'm going to create a function.

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So to create a function,
you first need to write Dev.

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Dev and then space and
then the name of the function.

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Let's say we want a
function that says hello.

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So I'm going to write, say hello.

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That is the name of the function.

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After the name of the
function, you need to open

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and close parentheses
and then add a column.

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After this, you can press enter.

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And as you can see, the marker here doesn't,
the cursor doesn't come back to here.

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It comebacks to here
with, as you can see here,

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one, two, three, four new spaces,
which is called the indentation.

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So you're going to write
everything under this

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function with an
indentation of four spaces.

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So I can write any instruction I want.

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So for example, print hello.

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Okay, that's a very basic
function that just says hello.

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So Dev, name of the function.

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So again, what you
can do if you want to add

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multiple words, you
can add an underscore.

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And then parentheses, column,

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and everything you write inside the
function will be with an indentation.

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Now, if I run that code, let's run the
main, you can see, well, we have nothing.

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Why is that?

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Because we have just created a function.

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Okay, we didn't call the function.

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Okay, if you just create,
if you just define a

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function like this, it's
not going to do anything.

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What you need to do in your
code is to call the function.

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To call the function, you just
write the name of the function.

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Okay, with the parentheses.

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And then you can run the program
again, and you can see hello.

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So the good thing about a function is that
you can actually call it multiple times.

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So I can just copy this
and paste it three times.

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And it's going to call
the function three times.

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You can see hello, hello, hello.

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So of course, make sure you
define the function before you call it.

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Okay, otherwise, you're
going to get an error.

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And then, well, as you
can see here, everything

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that is indented will
be under the function.

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So let's say I write
print, let's say I write test.

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Okay, I can run again, and you can
see hello, test, hello, test, hello, test.

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So if I continue to
add lines after this one,

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but with an indentation of four spaces,
it's going to be under the function.

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When I go back to the default
indentation of zero spaces,

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we are back to the main
program, and then so

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we can call the
function directly like this.