|
Functions in PHP : Tutorial
 |
 |
A function can be defined as a self-contained block of statements that perform a coherent task.
If a set of PHP statements does a cetain task (e.g finds if the number is even or odd) we can group it together as a function and hire it for doing that task when ever needed.
Syntax :
Function can takein None or N arguments
{ denotes start of a function body whereas } denotes the end of function body.
Example 1 : functions with no argruments
In the below example we have defined two functions greetings() and myDetails(). We call the function by the function name followed by () and a ; (semicolon). Note that the function name is case-insensitive.
We may call a function as many times as needed.
Example 2 : functions with argruments
In the below example function myDetails() takes in two argruments name and age.
Note that we call the function by passing two parameters/agruments myDetails($name,$age);
Example 3 :
A function can return values of any type arrays,integers,strings and objects.
When a return statement is encountered within a function it causes the function to end its execution immediately and pass control back to the line from which it was called.
Syntax :
If a set of PHP statements does a cetain task (e.g finds if the number is even or odd) we can group it together as a function and hire it for doing that task when ever needed.
Syntax :
function functionName($argument1, $argument2,....,$argumentN) {
//Statements
}
function is a pre-defined keyword in PHP.Function can takein None or N arguments
{ denotes start of a function body whereas } denotes the end of function body.
 |
Function names in PHP are case-insensitive. Function naming convenstions follow the same rules as that of variables in PHP. |
Example 1 : functions with no argruments
In the below example we have defined two functions greetings() and myDetails(). We call the function by the function name followed by () and a ; (semicolon). Note that the function name is case-insensitive.
We may call a function as many times as needed.
<?php
function greetings() {
echo "Hello there!<br>";
}
function myDetails() {
echo "My Name is Mike.<br>";
echo "In 19 years old.<br>";
}
greetings(); //function call
//Note that function names are case-insensitive
mydetails();
?>
Output
Hello there! My Name is Mike. In 19 years old.
Example 2 : functions with argruments
In the below example function myDetails() takes in two argruments name and age.
Note that we call the function by passing two parameters/agruments myDetails($name,$age);
<?php
function greetings() {
echo "Hello there!<br><br>";
}
function myDetails($name,$age) {
echo "My Name is $name.<br>";
echo "In $age years old.<br><br>";
}
greetings();
$name = "Natalia";
$age = 21;
//call 1
myDetails($name,$age);
$Myname = "Thomas";
$Myage = 24;
//call 2
myDetails($Myname,$Myage);
?>
Output
Hello there! My Name is Natalia. In 21 years old. My Name is Thomas. In 24 years old.
Example 3 :
<?php
function evenOdd($no) {
if($no/2 == 1)
{
echo "$no is Odd.<<br>";
}
else
{
echo "$no is Even.<br>";
}
}
function addition($a,$b) {
$sum = $a+$b;
echo "$a + $b = ".$sum."<br>";
}
function subtraction($a,$b) {
$diff = $a+$b;
echo "$a - $b = ".$diff."<br>";
}
function multiplication($a,$b) {
echo "$a * $b = ".$a*$b."<br>";
}
function division($a,$b) {
echo "$a / $b = ".$a/$b."<br>";
}
function modulus($a,$b) {
echo "$a % $b = ".$a%$b."<br>";
}
$no1 = 20;
$no2 = 10;
evenOdd($no1);
evenOdd($no2);
addition($no1,$no2);
subtraction($no1,$no2);
multiplication($no1,$no2);
division($no1,$no2);
modulus($no1,$no2);
?>
Output
20 is Even. 10 is Even. 20 + 10 = 30 20 - 10 = 30 20 * 10 = 200 20 / 10 = 2 20 % 10 = 0
Functions returning values
A PHP function can return values by return statement.A function can return values of any type arrays,integers,strings and objects.
When a return statement is encountered within a function it causes the function to end its execution immediately and pass control back to the line from which it was called.
Syntax :
function functionName($argument1, $argument2,....,$argumentN) {
//Statements
return value;
}
|
If a function has no return is by default value NULL is returned. |
<?php
function evenOdd($no) {
}
evenOdd($no1);
?>
Output