PHP array_walk() Function

<?php
// PHP program to illustrate array_walk()
// function
// user-defined callback function
function myfunction($value, $key)
{
    echo "The key $key has the value $value \n";
}
// Input array
$arr = array("a"=>"yellow", "b"=>"pink", "c"=>"purple");
// calling array_walk() with no extra parameter
array_walk($arr, "myfunction");
?>

<?php
// PHP program to illustrate array_walk()
// function
// user-defined callback function
function myfunction($value, $key, $extraParam)
{
    echo "The key $key $extraParam $value \n";
}
// Input array
$arr = array("a"=>"yellow", "b"=>"pink", "c"=>"purple");
// calling array_walk() with extra parameter
array_walk($arr, "myfunction", "has the value");
?>

<?php
// PHP program to illustrate array_walk()
// function
// user-defined callback function to 
// update array values - to update array 
// values, pass the first parameter by reference
function myfunction(&$value, $key)
{
    $value = $value + 10;
}
// Input array
$arr = array("first"=>10, "second"=>20, "third"=>30);
// calling array_walk() with no extra parameter
array_walk($arr, "myfunction");
// printing array after updating values
print_r($arr);
?>