PHP Functions is used to reuse php code. PHP Functions contains a piece of code which takes one or more parameter as input and make some processing on it and returns a value.
PHP provides more than 1000 of built-in library functions. But also we can create user defined custom function. PHP Functions reduces our writing code time by reusing same logic code .
Advantage of PHP Functions
Code Reusability: PHP functions are defined only once and can be used many times.
Less Code: It saves a lot of code to rewrite it again. You can write the logic only once and reuse it by the use of function.
Easy to understand: PHP functions separate the programming logic. So you can easy understand the flow of the application because every logic is separated in the form of functions.
Creating PHP Function
A user define function must start with keyword function and all the PHP code should be put inside { and } braces.A function will be executed by a call to the function.
PHP Syntax :
function function_name(){
//code for programming logic.
}
PHP Example :
<?php
function sitetitle() //user defined function
{
echo "Welcome to learning system";
}
sitetitle();//calling function
?>
Output:
Welcome to learning system
PHP Functions with Parameters
you can pass your parameters inside a function.You can add as many arguments as you want, just separate them with a comma. You can pass arguement by Call by Value (default), Call by Reference, Default argument values and Variable-length argument list.
PHP Example :
<?php
function sub($num1, $num2) {
$sub = $num1 - $num2;
echo "Substraction of the two numbers is : $sub";
}
sub(800, 546);
?>
Output:
Substraction of the two numbers is : 254
PHP Functions return value
A function can return a value using the return statement.
PHP Example :
<?php
function sub($num1, $num2) {
$sub = $num1 - $num2;
return $sub;
}
$return_sub=sub(230, 146);
echo "Substraction of the two numbers is : $return_sub";
?>
Output:
Substraction of the two numbers is : 84
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