Unit 1: PHP implementation and project work

php<?php
// 1. Check whether a number is prime
$n = 29; $prime = $n > 1;
for ($i = 2; $i * $i <= $n; $i++) if ($n % $i == 0) { $prime = false; break; }
echo $n . ($prime ? " is prime" : " is not prime") . "<br>";

// 2. Fibonacci series of 10 terms
$a = 0; $b = 1;
for ($i = 1; $i <= 10; $i++) { echo $a . " "; [$a, $b] = [$b, $a + $b]; }

// 3. Reverse a number and check palindrome
$num = 12321; $rev = 0; $t = $num;
while ($t > 0) { $rev = $rev * 10 + $t % 10; $t = intdiv($t, 10); }
echo "<br>" . ($rev == $num ? "Palindrome" : "Not palindrome");

// 4. Day name with switch
switch (date("N")) {
    case 6: case 7: echo "<br>Weekend"; break;
    default: echo "<br>Weekday";
}
?>

php<?php
function factorial(int $n): int {            // recursive function
    return $n <= 1 ? 1 : $n * factorial($n - 1);
}
function simpleInterest($p, $r = 8, $t = 1) { // default arguments
    return $p * $r * $t / 100;
}
echo factorial(5);                 // 120
echo simpleInterest(5000);         // 400
$f = "factorial"; echo $f(4);      // dynamic function call: 24
?>

php<?php
$s = "Synetic Business School";
echo strlen($s), "<br>";                 // length
echo strtoupper($s), "<br>";
echo strrev($s), "<br>";                 // reverse
echo str_word_count($s), "<br>";         // 3
echo ucwords(strtolower("pHp lAB")), "<br>";
echo str_replace("School", "College", $s), "<br>";
$clean = strtolower(preg_replace("/[^a-z]/i", "", "Madam"));
echo $clean === strrev($clean) ? "Palindrome string" : "Not palindrome";
// count vowels
echo preg_match_all("/[aeiou]/i", $s);
?>

php<?php
$marks = ["Aman" => 78, "Riya" => 91, "Kabir" => 66, "Simran" => 84];
arsort($marks);                              // sort by value, high to low
foreach ($marks as $name => $m) echo "$name: $m<br>";
echo "Average: " . array_sum($marks) / count($marks);
echo "Topper: " . array_key_first($marks);

// matrix addition
$A = [[1, 2], [3, 4]]; $B = [[5, 6], [7, 8]];
for ($i = 0; $i < 2; $i++) {
    for ($j = 0; $j < 2; $j++) echo ($A[$i][$j] + $B[$i][$j]) . " ";
    echo "<br>";
}
?>

php<?php
$result = "";
if ($_SERVER["REQUEST_METHOD"] === "POST") {
    $a = (float) $_POST["a"]; $b = (float) $_POST["b"]; $op = $_POST["op"];
    $result = match ($op) {
        "+" => $a + $b, "-" => $a - $b, "x" => $a * $b,
        "/" => $b != 0 ? $a / $b : "Cannot divide by zero",
    };
}
?>
<form method="post">
  <input name="a" type="number" step="any" required>
  <select name="op"><option>+</option><option>-</option><option>x</option><option>/</option></select>
  <input name="b" type="number" step="any" required>
  <button>Calculate</button>
</form>
<p>Result: <?= htmlspecialchars((string) $result) ?></p>

• Also practise: a registration form with validation (name, email, mobile, gender radio, hobbies checkboxes) that redisplays errors and entered values.

php<?php
// Visitor counter stored in a file
$file = "counter.txt";
$count = file_exists($file) ? (int) file_get_contents($file) : 0;
file_put_contents($file, ++$count);
echo "You are visitor number $count";

// Read a CSV file into an HTML table
echo "<table border='1'>";
if (($h = fopen("students.csv", "r")) !== false) {
    while (($row = fgetcsv($h)) !== false) {
        echo "<tr><td>" . implode("</td><td>", array_map("htmlspecialchars", $row)) . "</td></tr>";
    }
    fclose($h);
}
echo "</table>";
?>

sqlCREATE DATABASE college;
USE college;
CREATE TABLE student (
  roll INT AUTO_INCREMENT PRIMARY KEY,
  name VARCHAR(50) NOT NULL,
  course VARCHAR(20),
  marks INT
);

php<?php
// db.php — included by every page
$conn = new mysqli("localhost", "root", "", "college");
if ($conn->connect_error) die("Connection failed");

// add.php — insert from a form
require "db.php";
$stmt = $conn->prepare("INSERT INTO student (name, course, marks) VALUES (?, ?, ?)");
$stmt->bind_param("ssi", $_POST["name"], $_POST["course"], $_POST["marks"]);
$stmt->execute();

// list.php — display with edit and delete links
$res = $conn->query("SELECT * FROM student ORDER BY roll");
while ($r = $res->fetch_assoc()) {
    echo htmlspecialchars($r["name"]) . " — " . $r["marks"] .
         " <a href='edit.php?roll={$r['roll']}'>Edit</a>" .
         " <a href='delete.php?roll={$r['roll']}'>Delete</a><br>";
}
?>

• GET/POST feedback form: read with $_POST, validate, and display a thank-you message.
• Contact form saved to a text file: file_put_contents("contacts.txt", "$name,$email\n", FILE_APPEND);
• Session login:

php<?php
session_start();
if ($_POST["user"] === "admin" && password_verify($_POST["pwd"], $hash)) {
    $_SESSION["user"] = "admin";
    header("Location: dashboard.php");
} else {
    echo "Invalid login";
}
?>

Protect each private page with if (!isset($_SESSION["user"])) header("Location: login.php");

php<?php
// Remember the user's preferred theme for 30 days
if (isset($_GET["theme"])) setcookie("theme", $_GET["theme"], time() + 2592000);
$theme = $_COOKIE["theme"] ?? "light";
// Logout
session_start(); $_SESSION = []; session_destroy();
?>

Choose a blog system, inventory manager or task tracker with CRUD features, login and a clean layout.

• Git basics: git init, git add ., git commit -m "message", git push to GitHub.
• Deployment: upload files and the exported database to free hosting (for example InfinityFree) or demonstrate on localhost.