php functions

Php functions

<?php  

function sayHello(){  

echo "Hello PHP Function";  

}  

sayHello();//calling function  

?>  

Hello PHP Function

PHP Function Arguments

<?php  

function sayHello($name){  

echo "Hello $name<br/>";  

}  

sayHello("Sonoo");  

sayHello("Vimal");  

sayHello("John");  

?>  

Output

Hello Sonoo

Hello Vimal

Hello John

Php function with arguments

<?php  

function sayHello($name,$age){  

echo "Hello $name, you are $age years old<br/>";  

}  

sayHello("Sonoo",27);  

sayHello("Vimal",29);  

sayHello("John",23);  

?>  

Output

Hello Sonoo, you are 27 years old

Hello Vimal, you are 29 years old

Hello John, you are 23 years old

Php call by reference

<?php  

function adder(&$str2)  

{  

    $str2 .= 'Call By Reference';  

}  

$str = 'Hello ';  

adder($str);  

echo $str;  

?>  

Hello Call By Reference

PHP Function: Default Argument Value

<?php  

function sayHello($name="Sonoo"){  

echo "Hello $name<br/>";  

}  

sayHello("Rajesh");  

sayHello();//passing no value  

sayHello("John");  

?>  

Output

Hello Rajesh

Hello Sonoo

Hello John

PHP Function: Returning Value

<?php  

function cube($n){  

return $n*$n*$n;  

}  

echo "Cube of 3 is: ".cube(3);  

?>  

Cube of 3 is: 27

function using input

<?php  

//add() function with two parameter  

function add($x,$y)    

{  

$sum=$x+$y;  

echo "Sum = $sum <br><br>";  

}  

//sub() function with two parameter  

function sub($x,$y)    

{  

$sub=$x-$y;  

echo "Diff = $sub <br><br>";  

}  

//call function, get  two argument through input box and click on add or sub button  

if(isset($_POST['add']))  

{  

//call add() function  

 add($_POST['first'],$_POST['second']);  

}     

if(isset($_POST['sub']))  

{  

//call add() function  

sub($_POST['first'],$_POST['second']);  

}  

?>  

<form method="post">  

Enter first number: <input type="number" name="first"/><br><br>  

Enter second number: <input type="number" name="second"/><br><br>  

<input type="submit" name="add" value="ADDITION"/>  

<input type="submit" name="sub" value="SUBTRACTION"/>  

</form>     

PHP Call By Value

<?php  

function adder($str2)  

{  

    $str2 .= 'Call By Value';  

}  

$str = 'Hello ';  

adder($str);  

echo $str;  

?>  

Hello

php call by refernce

<?php  

function adder(&$str2)  

{  

    $str2 .= 'Call By Reference';  

}  

$str = 'This is ';  

adder($str);  

echo $str;  

?>  

output

This is Call By Reference

$a .= $b => $a = $a.$b



ist str loads by this is and addr functions calls with argument of $str, it gets the value which is in address of variable a, variable stores some value, that variable has address
the value loads in loads in str2, concatenate and prints

calles the address

call by referencve

1. <?php  
2. function increment(&$i)  
3. {  
4.     $i++;  
5. }  
6. $i = 10;  
7. increment($i);  
8. echo $i;  
9. ?>  

output

11

PHP Variable Length Argument Function

1. <?php  
2. function add(...$numbers) {  
3.     $sum = 0;  
4.     foreach ($numbers as $n) {  
5.         $sum += $n;  
6.     }  
7.     return $sum;  
8. }  
9.   
10. echo add(1, 2, 3, 4);  
11. ?>  

to do factorials

1. <?php    
2. function factorial($n)    
3. {    
4.     if ($n < 0)    
5.         return -1; /*Wrong value*/    
6.     if ($n == 0)    
7.         return 1; /*Terminating condition*/    
8.     return ($n * factorial ($n -1));    
9. }    
10.     
11. echo factorial(5);    
12. ?>    

first it retursn 5*factorial(5-1), in second loop 5 alrady there, 4* factorial(3)

loop