Using closure

<?php
// Our closure
$double = function($a) {
    return $a * 2;
};

// This is our range of numbers
$numbers = range(1, 5);

// Use the closure as a callback here to
// double the size of each element in our
// range
$new_numbers = array_map($double, $numbers);

print implode(' ', $new_numbers);
?>

To solve the following closure program without using callback and closure.

We can achieve the same result as the array_map() example without using array_map() and callbacks by using a traditional for loop. Here's how you can do it:

// A function to double a number
function double($num) {
    return $num * 2;
}

// An array of numbers
$numbers = [1, 2, 3, 4, 5];

// Create a new array to store the doubled values
$new_numbers = [];

// Loop through each element of the $numbers array and double the value
for ($i = 0; $i < count($numbers); $i++) {
    $new_numbers[] = double($numbers[$i]);
}

print_r($new_numbers);

Output:

Array
(
    [0] => 2
    [1] => 4
    [2] => 6
    [3] => 8
    [4] => 10
)

In this alternative approach, we manually loop through each element of the $numbers array using a for loop. We call the double() function on each element and add the doubled value to the $new_numbers array using the [] syntax to push the value to the end of the array.

While using array_map() and callbacks can make the code more concise and expressive, the for loop method is an alternative when you want to avoid using callbacks or prefer a more traditional looping approach. Both methods achieve the same result in this case.