PHP Functions & Modular Code

<?php

$userSession = [
    'user_id' => 42,
    'username' => 'alex_dev',
    'roles' => ['admin', 'developer']
];

$serialized = serialize($userSession);
echo "Serialized String:\n$serialized\n\n";

$unserialized = unserialize($serialized);
echo "Unserialized Array:\n";
print_r($unserialized);
?>

Serialized String:
a:3:{s:7:"user_id";i:42;s:8:"username";s:8:"alex_dev";s:5:"roles";a:2:{i:0;s:5:"admin";i:1;s:9:"developer";}}

Unserialized Array:
Array
(
    [user_id] => 42
    [username] => alex_dev
    [roles] => Array
        (
            [0] => admin
            [1] => developer
        )

)

<?php

$scores = [
    "Math" => 95,
    "Science" => 88,
    "English" => 92
];

echo "Subject Scores:\n";
foreach ($scores as $subject => $score) {
    echo "- $subject: $score\n";
}
?>

Subject Scores:
- Math: 95
- Science: 88
- English: 92

<?php

function greet(string $name, string $greeting = "Hello"): string {
    return "$greeting, $name!";
}

echo greet("Alice") . "\n";
echo greet("Bob", "Good morning") . "\n";
?>

Hello, Alice!
Good morning, Bob!

<?php

function processItem($item, callable $callback) {
    return $callback($item);
}

$uppercase = function($str) {
    return strtoupper($str);
};

$result = processItem("hello php developers", $uppercase);
echo "Callback Output: $result\n";
?>

Callback Output: HELLO PHP DEVELOPERS

<?php

$config = [
    'app_name' => 'OperateTools',
    'debug_mode' => true,
    'max_users' => 500,
    'version' => '2.5.0'
];

foreach ($config as $key => $value) {
    $displayValue = is_bool($value) ? ($value ? 'true' : 'false') : $value;
    echo "Key: [$key] => Value: $displayValue\n";
}
?>

Key: [app_name] => Value: OperateTools
Key: [debug_mode] => Value: true
Key: [max_users] => Value: 500
Key: [version] => Value: 2.5.0