Functions Video Lecture | PHP for beginners - Software Development

Oh YouTube welcome to tutorial number 18
in the PHP programming series and in
this video we're going to learn about
functions now the first thing we're
going to do is create a basic function
that M don't take any parameters but
just does something so let's just create
our PHP file and we'll just save this as
function dot PHP and inside this file
we're going to create a function now to
create a phone function the syntax is e
type function and after this we're going
to type the name of the function me to
give a name and this is going to be kind
of like a welcome message so I'm going
to call this function welcome and then
after that we'll have two empty brackets
and I'll talk about those later okay so
the code that you want to be executed
when this function is called will be in
curly brackets so this function welcome
all I'm going to do is echo out welcome
to the website so here when we type
function we are telling PHP that this is
going to be a function let me give the
function name with two empty brackets
which will be discussed later and when
this function is called the code inside
of these brackets will be executed so
let's just call this function we're
going to echo welcome save that and then
we'll go to M function is it PHP and
you'll see that the function has been
carried out welcome to the website so
what we can do now is we can start
adding parameters in here and parameters
are things that can be kind of edited it
when you call a function so we can
actually declare variables inside of
this function when we create it so I'm
just going to create a variable called
name and what that will do is when this
function is created it's going to create
a variable called name and right now
this variable has no value at all so we
go on to end say welcome to the website
and then
can catenate name and we save this and
then we'll reload it and we've got
missing one argument for welcome and
you'll notice that is because since we
have a variable declared in here we need
to give it a value here when we call a
function so if you want to call welcome
what we're going to do is echo out I'm
going to type welcome and then inside
these brackets we can type the name of
the person so when I type Chris and
we'll save that reload it and it says
welcome to the website Chris as you'll
probably add a space as well just to
make it look a little nicer reload that
welcome to the website - Chris so let's
just go over this so we understand
what's going on so this function is this
squared is saying okay we're going to
create a function our name is welcome
and it has one parameter which is the
variable name and then when we what when
we call this function what is going to
do is echo out welcome to the website
and then go back to this parameter of
name so one more when we are calling the
function down here when I say welcome
and we're passing this variable as a
value for name so what if we want to
have more than one parameter well we all
we do is add a comma just like we do
with arrays and we're going to have a
new one called age and then most islands
we're welcome to the website name and my
. you are and then we'll concatenate the
variable age years old slowly is on
there okay so now that we have another
variable here M another value that we
are passing through this and function
let's just reload that and you know
you'll notice we are missing argument
two for welcome so we go back to the
file all we do is put a comma and then
I'm going to say 18 as the value save
that and then welcome to apply Croatia
were 18 years old so what we can also do
with this is maybe create a useful
function you know a mathematical like a
calculator so we're going to create a
function here called add
I want to do is make a variable number
one comment num2 and what this will do
is it's going to M a whole and no 1 plus
num2 and then we end up and let's just
go out add and inside these brackets
we'll have 10 and 15 so if we save this
and we have a par sorry on line 6 let's
see what the error was I've actually
added a normal bracket instead of curly
bracket I apologize for that and you'll
see it's other than numbers 225 so all
you can see is doing here is what we're
doing is we're creating a function
called add and the two parameters inside
of the function are num1 and num2 and
then when this function is called it's
going to add together number one and
number two but this isn't a very
practical way or professional way of
creating a function so what we want to
do now is we're going to use the routine
and what we're going to do is we'll just
create a new function called subtract
and we'll just create the same variables
and then 1 and num2 and then we'll have
our curly brackets here and we'll make
our mathematical equation here we're
going to create a variable called total
now is going to equal no 1 plus num2 and
i'm not going to do is simply return
total so now we can do is go down here
and actually I'm going to change this to
subtract and I also need a semicolon
there so we're going to do now is just
simply take out echo subtract and then
num1 actually show you need to get a
value it's going to be 10 and 4 ok so we
save this is your deck about 6 and there
we go
and
so you don't actually don't have to when
you are calling a function so if the
function is just going to echo out num1
- num2 you actually don't have to use
echo the caller function so you can just
type out subtract and then just do five
and two should output three because the
function already contains echo but it's
kind of like a habit of mine to do that
I don't know why but you know it works
both ways but it's more professional
just to call the function like this so
that is the tutorial on functions so
today we've learned that we can create a
function using the function keyword then
we'll give the function a name and
inside of the two curly brackets will
hold the code to be executed when the
function is run and the caller function
all we need to do is type out the name
or we can use the echoing function but
you know it's just probably more
professional teach qala function using
the name we can also add parameters to
the function so here I've added num1 as
a parameter and num2 and this will
declare the variables inside of the
parameters separated by a comma and we
can use these variables only inside of
this function and then we set these
parameters when we call a function just
by typing the value in the corresponding
place to the actual when the function is
created so if you have any questions
about this please leave a comment and
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the channel thank you for watching and
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