PHP Lesson 3 – Creating Functions

How to create Functions in PHP and also how to Pass Variables to Functions.


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PHP has hundreds of predefined functions (maybe thousands). This tutorial gives examples on how to create your own php functions. There are two rules I would like to share with you before we start.

Rule 1:
Make sure your new function name does not exhist. You can check for a complete list of PHP predefined functions.

Rule 2:
Do not declare/define the same function more than once inside the same file. You will get an error.

OK, let’s create our first function. This function will display a text advertisement. We will call this function ads().

Source Code

// first define the function
function ads()
echo “Visit for free tutorials”;
// now call the function ads() like so

Now you can display the same ad however many times you want just by calling the function ads().

Passing Values to Functions:

Let’s say we want to randomly display three ads. We could do this by placing three text ads inside our ads() function and then passing a random value to it, to indicate which ad to display. We can do this by using a parameter variable inside the function. For example $n will be the variable and this is how it is placed inside our ads function like so “ads($n)”. This variable holds a copy of the value passed to it.

Now we need to set $n to a random number between 1 and 3. We can do this by using one of PHP pre-defined functions called rand(). If you want a random number between 1 and 3 (inclusive), for example, use “rand (1, 3)”. To make this a little more clear, view the code below:

Source Code


// first define the function

function ads($n)

$a = “”;

if($n == 1)
echo “<a href=’$a’>Visit for free tutorials</a>”;

if($n == 2)
echo “<a href=’$a’> for PHP and much more!</a>”;

if($n == 3)
echo “<a href=’$a’>PHP is Number One!</a>”

} // end of function

// define the random value for $n
$n = rand (1, 3);

// now call the function ads() with the value $n


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