How to Call a PHP Function

Let's say we have a function func that returns some text:

<?php
	function func()
	{
		return 'text';
	}
?>

To call our function, we need to write its name and parentheses, like this: func. We can either output the function's result directly to the screen, or store it in a variable and then do something with it.

Let's output the result of our function to the screen as an example:

<?php
	function func()
	{
		return 'text';
	}
	
	echo func(); // outputs 'text'
?>

Now let's store the function's result in a variable:

<?php
	function func()
	{
		return 'text';
	}
	
	$str = func();
?>

Now let's say we have a function that takes a number as a parameter and returns the square of that number:

<?php
	function square($num)
	{
		return $num * $num;
	}
?>

Let's find the square of the number 3 using this function:

<?php
	function square($num)
	{
		return $num * $num;
	}
	
	echo square(3); // outputs 9
?>

Now let's not output the square of three directly, but first store it in a variable, then add the number 1 to this variable, and output the result to the screen:

<?php
	function square($num)
	{
		return $num * $num;
	}
	
	$res = square(3);
	echo $res + 1; // outputs 10
?>