User Defined Functions

User Defined Functions

User Defined Functions : 

1.       Function<function_name>(arg1,arg2,arg3,……..argn)

{

  Body of the function

}

2.       Any valid php code may appear inside a function. Function name follows the same rules as variable naming rules in php. A function will be executed by a call to the function.

3.       “Return  “ script used inside a function to return a vlaue back to the caller.

          <?php

 function writename()

 {

                                                 echo "<h1> Chandu</h1>";

 }

 ?>

 <?php

  writename();

  writename();

  ?>

Functions – passing and returning parameters:

             <?php

function addname($x,$y)

{

    $r= $x+$y;

    return $r;

}

?>

<h1>

    <?php

    echo "sum".addnum(11,22)."<br>";

    $c=  addname("India","Tech");

    echo "res=. $c;

    <?

</h1>

A parameter can be passed to a function using two techniques.

1.       Pass by value:

Here what ever changes happened to the parameter passed in a function will not gets reflected in the caller.

           <?php

           function change($x)

               {

                   $x=22;

   

                }

                    ?>

             <?php

              $x=10;

              echo $x."<br>";

               change($x);

                echo $x;

                 ?>

2.       Pass by reference:

Here what ever changes happens to the parameter pass the function will gets reflected in the caller.

<?php

function change($x)

{

    $x=22;

   

}

?>

<?php

$x=10;

echo $x."<br>";

change($x);

echo $x;

?>