Functions
In PHP, a function is a piece of code which takes one or more inputs in the form of parameters and does some processing then returns a value. You already have seen many functions like echo()
, print_r()
, var_dump()
, etc. These are built-in functions, but PHP also allows you to create your own functions.
Defining a Function
A function is defined using the function
keyword, followed by a name and parentheses ()
:
<?php
function writeMsg() {
echo "Hello world!";
}
writeMsg(); // call the function
?>
Function Parameters
Information can be passed to functions through parameters:
phpCopy code<?php
function familyName($fname) {
echo "$fname Smith.<br>";
}
familyName("Jani");
familyName("Hege");
familyName("Stale");
familyName("Kai Jim");
familyName("Borge");
?>
Function Return Value
A function can return a value using the return
statement:
phpCopy code<?php
function sum($x, $y) {
$z = $x + $y;
return $z;
}
echo "5 + 10 = " . sum(5, 10) . "<br>";
echo "7 + 13 = " . sum(7, 13) . "<br>";
echo "2 + 4 = " . sum(2, 4);
?>
Functions are a way of encapsulating functionality that you wish to reuse. It makes your code more modular and easier to understand.
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