Page 87 - Open Soource Technologies 304.indd

Unit 4: Functions

Example: Notes

<?php
function test() {
$x = 8;

echo $x;
}

echo $x; //

test(); // 8
?>

The “echo $x” expression outside the function returns an error because the $x variable is not
defined or recognized outside the test() function, but the “echo” statement inside function refers
to a local $x variable, which is defined within test() function.

Another example:

<?php
$x = 8;

function test() {
echo $x;

}

echo $x; // 8
test(); //

?>
This time, the $x variable is defined outside the function, but not inside it.

As you can see, the calling function returns an error notice, because the “echo” statement refers
to a local version of the $x variable, and it has not been assigned a value within this scope.

4.3.1 Global Variables
A global variable can be accessed in any part of the program.

If you want to use inside a function a variable defined outside it, that variable must be explicitly
declared to be global in the function. This is accomplished by placing the keyword GLOBAL (or
global) in front of the variable that should be recognized as global (or more variables separated
by comma). This will extends the scope of that variable inside the function.

LOVELY PROFESSIONAL UNIVERSITY 81