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PHP Functions
The real power of PHP comes from its functions. There are more than about 1000 built-in functions available in PHP, which is much enough to perform a lot of task.
PHP5 Functions
You are free to create your own functions (user-defined functions). A function is basically a block of code that can be used to perform some particular task in your program.
Create a Function in PHP
A function in PHP is created with the help of function keyword. Here is the general form to declare a function in PHP:
function functionName() { code to be executed here; }
Here, function is the keyword used in declaring the function in PHP, functionName is the name of the function. You can give a name to the function starting with a letter or underscore (but not with a number).
PHP Functions Example
Here is an example, creates a function named writeMsg(), to write a message as output:
<!DOCTYPE html> <html> <head> <title>PHP function Example</title> </head> <body> <?php function writeMsg() { echo "This is PHP function tutorial."; } writeMsg(); ?> </body> </html>
Here is the output produced by the above PHP script:

A function with parameters is known as parameterized function in PHP.
Here is another example, uses function with parameters in PHP:
<html> <head> <title>Writing PHP Function with Parameters</title> </head> <body> <?php function addFunction($num1, $num2) { $sum = $num1 + $num2; echo "Sum of the passed numbers is : $sum"; } addFunction(100, 200); ?> </body> </html>
Here is the output of this PHP script:

Let's take another example also demonstrating functions in PHP with parameter.
<html> <head> <title>Function Example in PHP</title> </head> <body> <?php function printTable($num) { for($i=1;$i<=10;$i++) { echo $num*$i; echo " "; } } printTable(2); echo "<br/>"; printTable(3); echo "<br/>"; printTable(4); echo "<br/>"; ?> </body> </html>
Here is the sample output produced by the above parameterized function in PHP example.

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