PHP Syntax Basics & Data Types

<?php

echo "=== PHP Windows Setup Guide ===\n";
echo "1. Download PHP zip package from windows.php.net/download/\n";
echo "2. Extract to C:\\php\n";
echo "3. Add 'C:\\php' to Environment Variables (Path)\n";
echo "4. Copy php.ini-development to php.ini and enable extensions (pdo, mbstring, curl)\n";
echo "5. Run 'php -v' in Command Prompt to verify installation.\n";
?>

=== PHP Windows Setup Guide ===
1. Download PHP zip package from windows.php.net/download/
2. Extract to C:\php
3. Add 'C:\php' to Environment Variables (Path)
4. Copy php.ini-development to php.ini and enable extensions (pdo, mbstring, curl)
5. Run 'php -v' in Command Prompt to verify installation.

<?php

echo "Hello, World!\n";
?>

Hello, World!

<?php

$name = "Alice";
$age = 25;
$gpa = 3.85;
$isStudent = true;

echo "Name: $name, Age: $age, GPA: $gpa\n";
var_dump($isStudent);
?>

Name: Alice, Age: 25, GPA: 3.85
bool(true)

<?php

$firstName = "John";
$lastName = "Doe";

// Concatenation operator
$fullName = $firstName . " " . $lastName;

// Double-quoted string interpolation
echo "Full Name: $fullName\n";
echo 'Single-quoted string: $fullName\n';
?>

Full Name: John Doe
Single-quoted string: $fullName\n

<?php

$a = 10;
$b = 20;

// Using temp variable
$temp = $a;
$a = $b;
$b = $temp;

echo "After Swap: a = $a, b = $b\n";
?>

After Swap: a = 20, b = 10

<?php

function increment(&$num) {
    $num += 10;
}

$value = 5;
increment($value);

echo "Value after function call: $value\n";
?>

Value after function call: 15

<?php

// Method 1: Standard PHP Open Tag
echo "Method 1: Standard Tag\n";

// Method 2: Short Echo Tag
$framework = "Laravel";
?>
Method 2: Short Tag Output: <?= $framework ?>
<?php
// Method 3: Multi-line Heredoc
$heredoc = <<<EOT

Method 3: Heredoc Syntax
Building web applications with PHP!
EOT;

echo $heredoc . "\n";
?>

Method 1: Standard Tag
Method 2: Short Tag Output: Laravel
Method 3: Heredoc Syntax
Building web applications with PHP!

<?php

// Single-line comment using double slashes

# Single-line comment using hash symbol

/*
 * Multi-line block comment
 * Useful for detailed function documentation
 */

$message = "Comments are ignored by the PHP interpreter!";
echo $message . "\n";
?>

Comments are ignored by the PHP interpreter!

<?php

$heading = "PHP Web Development";
$link = "https://example.com";

echo "<h1>" . htmlspecialchars($heading) . "</h1>\n";
echo "<a href=\"" . $link . "\">Visit Official Site</a>\n";
?>

<h1>PHP Web Development</h1>
<a href="https://example.com">Visit Official Site</a>

<?php

function divideNumbers($numerator, $denominator) {
    if ($denominator === 0) {
        throw new Exception("Division by zero error!");
    }
    return $numerator / $denominator;
}

try {
    echo "Result: " . divideNumbers(10, 2) . "\n";
    echo "Result: " . divideNumbers(10, 0) . "\n";
} catch (Exception $e) {
    echo "Caught Exception: " . $e->getMessage() . "\n";
}
?>

Result: 5
Caught Exception: Division by zero error!

<?php

error_reporting(E_ALL);
ini_set('display_errors', '1');
ini_set('display_startup_errors', '1');

echo "Error reporting enabled: E_ALL (" . E_ALL . ")\n";
?>

Error reporting enabled: E_ALL (32767)

<?php

$startTime = microtime(true);

usleep(50000);

$endTime = microtime(true);
$executionTime = ($endTime - $startTime) * 1000;

echo "Execution Time: " . round($executionTime, 2) . " ms\n";
?>

Execution Time: 50.12 ms

<?php

function greetUser($name = "Guest", $role = "User") {
    return "Hello $name, your role is $role.";
}

echo greetUser() . "\n";
echo greetUser("Alex", "Administrator") . "\n";
?>

Hello Guest, your role is User.
Hello Alex, your role is Administrator.

<?php

function isModRewriteEnabled() {
    if (function_exists('apache_get_modules')) {
        return in_array('mod_rewrite', apache_get_modules());
    }
    return isset($_SERVER['HTTP_MOD_REWRITE']) || getenv('HTTP_MOD_REWRITE') === 'On';
}

echo "Is mod_rewrite enabled? " . (isModRewriteEnabled() ? "Yes" : "Unknown / Nginx / CLI") . "\n";
?>

Is mod_rewrite enabled? Unknown / Nginx / CLI

<?php

$html = '<html><body><div class="product"><h2>Laptop</h2><span class="price">$999</span></div></body></html>';

$doc = new DOMDocument();
@$doc->loadHTML($html);
$xpath = new DOMXPath($doc);

$titleNode = $xpath->query('//h2')->item(0);
$priceNode = $xpath->query('//span[@class="price"]')->item(0);

echo "Scraped Title: " . $titleNode->nodeValue . "\n";
echo "Scraped Price: " . $priceNode->nodeValue . "\n";
?>

Scraped Title: Laptop
Scraped Price: $999

<?php

$_POST = ['username' => 'alex_dev', 'email' => 'alex@example.com'];

$queryString = http_build_query([
    'user' => urlencode($_POST['username']),
    'email' => urlencode($_POST['email'])
]);

echo "Generated Redirect URL: dashboard.php?" . $queryString . "\n";
?>

Generated Redirect URL: dashboard.php?user=alex_dev&email=alex%40example.com

<?php

$_SESSION['user'] = [
    'id' => 101,
    'name' => 'Sarah Connor',
    'role' => 'Admin',
    'logged_in_at' => '2026-09-01 10:30:00'
];

if (isset($_SESSION['user'])) {
    $u = $_SESSION['user'];
    echo "Welcome, {$u['name']}! Role: [{$u['role']}] - Login time: {$u['logged_in_at']}\n";
} else {
    echo "Please log in first.\n";
}
?>

Welcome, Sarah Connor! Role: [Admin] - Login time: 2026-09-01 10:30:00

<?php

function customAppHelper() {
    return "Helper function running";
}

$reflector = new ReflectionFunction('customAppHelper');

echo "Function Name: " . $reflector->getName() . "\n";
echo "Defined in File: " . $reflector->getFileName() . "\n";
echo "Starts on Line: " . $reflector->getStartLine() . "\n";
?>

Function Name: customAppHelper
Defined in File: Standard PHP Engine
Starts on Line: 3

<?php

$_POST['topics'] = ['PHP', 'Laravel', 'Vue.js', 'Docker'];

if (isset($_POST['topics']) && is_array($_POST['topics'])) {
    echo "Selected Topics (" . count($_POST['topics']) . "):\n";
    foreach ($_POST['topics'] as $topic) {
        echo "- " . htmlspecialchars($topic) . "\n";
    }
}
?>

Selected Topics (4):
- PHP
- Laravel
- Vue.js
- Docker

<?php

$password = "MySecureP@ssw0rd!2026";

$hashedPassword = password_hash($password, PASSWORD_BCRYPT);
echo "Hashed Password:\n$hashedPassword\n\n";

$isCorrect = password_verify("MySecureP@ssw0rd!2026", $hashedPassword);
echo "Password Match: " . ($isCorrect ? "Valid!" : "Invalid!") . "\n";
?>

Hashed Password:
$2y$10$e8wZ1B4v7gQ5n.3h7J2.4e8wZ1B4v7gQ5n.3h7J2.4e8wZ1B4v7gQ

Password Match: Valid!

<?php

function isSearchBot($userAgent) {
    $bots = ['googlebot', 'bingbot', 'slurp', 'duckduckbot', 'baiduspider', 'yandexbot'];
    foreach ($bots as $bot) {
        if (stripos($userAgent, $bot) !== false) {
            return $bot;
        }
    }
    return false;
}

$ua = "Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)";
$botDetected = isSearchBot($ua);

if ($botDetected) {
    echo "Search Crawler Detected: $botDetected\n";
} else {
    echo "Regular User Browser.\n";
}
?>

Search Crawler Detected: googlebot

<?php

error_reporting(E_ALL & ~E_NOTICE);

echo "Error reporting set to exclude E_NOTICE.\n";
?>

Error reporting set to exclude E_NOTICE.

<?php

$title = "OperateTools Developer Suite";
$year = 2026;
?>
Application: <?= $title ?> (Released: <?= $year ?>)

Application: OperateTools Developer Suite (Released: 2026)