CASE STUDY — Chapter 7: PHP Array Object

<?php
// Array ជា variable ផ្ទុកតម្លៃច្រើន
$fruits = ["Apple", "Banana", "Orange"];
echo $fruits[0]; // Apple
echo $fruits[1]; // Banana

// បង្ហាញជា Table ដោយប្រើ foreach
echo "<table border='1'>";
echo "<tr><th>#</th><th>Fruit</th></tr>";
foreach ($fruits as $i => $fruit) {
    echo "<tr><td>" . ($i + 1) . "</td><td>$fruit</td></tr>";
}
echo "</table>";
?>

<?php
// 1) Indexed (Numeric) Array — key ជាលេខ
$colors = ["Red", "Green", "Blue"];
echo $colors[0]; // Red

// 2) Associative Array — key ជា string
$student = [
    "name"  => "Sokha",
    "age"   => 20,
    "major" => "IT"
];
echo $student["name"]; // Sokha

// 3) Multidimensional Array — Array ក្នុង Array
$matrix = [
    [1, 2, 3],
    [4, 5, 6]
];
echo $matrix[1][2]; // 6
?>

<?php
// Scalar Variable — ផ្ទុកតម្លៃតែ 1
$name = "Sokha";
$age  = 20;

// Array Variable — ផ្ទុកតម្លៃច្រើនក្នុង variable មួយ
$names = ["Sokha", "Dara", "Vanna"];
$ages  = [20, 21, 22];

echo $name;     // Sokha (scalar: តម្លៃ 1)
echo $names[0]; // Sokha (array: index 0)
echo $names[1]; // Dara  (array: index 1)
?>

<?php
// Multidimensional Array — Array ដែលមាន Array នៅខាងក្នុង
$students = [
    ["name" => "Sokha", "score" => 85],
    ["name" => "Dara",  "score" => 90],
    ["name" => "Vanna", "score" => 78]
];

// Access ដោយ [$row]["key"]
echo $students[0]["name"];  // Sokha
echo $students[1]["score"]; // 90

// forEach ដើម្បី Loop ទិន្នន័យ
foreach ($students as $s) {
    echo $s["name"] . " => " . $s["score"] . "<br>";
}
?>

<?php
// Numeric Array — key = 0, 1, 2 ...
$fruits = ["Apple", "Banana", "Orange"];
echo $fruits[0]; // Apple (access ដោយ index លេខ)

// Associative Array — key = string
$person = [
    "name" => "Sokha",
    "age"  => 20,
    "city" => "Phnom Penh"
];
echo $person["name"]; // Sokha (access ដោយ key string)

// Numeric:     $arr[0], $arr[1]     — index ជាលេខ
// Associative: $arr["key"]          — key ជាឈ្មោះ (string)
?>

<?php
// Practical 1: Book Information — Associative Array + foreach
$books = [
    ["BookID"=>"B001", "Title"=>"HTML & CSS",      "Author"=>"Jon Duckett",     "Price"=>15.00, "Year"=>2020],
    ["BookID"=>"B002", "Title"=>"PHP & MySQL",      "Author"=>"Luke Welling",    "Price"=>20.00, "Year"=>2021],
    ["BookID"=>"B003", "Title"=>"JavaScript",       "Author"=>"David Flanagan",  "Price"=>18.50, "Year"=>2019],
    ["BookID"=>"B004", "Title"=>"Python Basics",    "Author"=>"Al Sweigart",     "Price"=>12.00, "Year"=>2022],
    ["BookID"=>"B005", "Title"=>"Java Programming", "Author"=>"Herbert Schildt", "Price"=>25.00, "Year"=>2023],
];

echo "<table border='1'>";
echo "<tr><th>#</th><th>BookID</th><th>Title</th><th>Author</th><th>Price ($)</th><th>Year</th></tr>";

$no = 1;
foreach ($books as $book) {
    echo "<tr>";
    echo "<td>$no</td>";
    echo "<td>{$book['BookID']}</td>";
    echo "<td>{$book['Title']}</td>";
    echo "<td>{$book['Author']}</td>";
    echo "<td>" . number_format($book['Price'], 2) . "</td>";
    echo "<td>{$book['Year']}</td>";
    echo "</tr>";
    $no++;
}
echo "</table>";
?>

<?php
// Practical 2: Subject/Score — Numeric Array + foreach
$subjects = ["PHP", "HTML", "CSS", "JavaScript", "MySQL", "C++"];
$scores   = [90, 100, 89, 98, 90, 95];

// Grade function
function getGrade($avg) {
    if ($avg >= 95) return "A";   // >= 95
    if ($avg >= 90) return "B";   // 90 – 94.99
    if ($avg >= 80) return "C";   // 80 – 89.99
    if ($avg >= 70) return "D";   // 70 – 79.99
    if ($avg >= 60) return "E";   // 60 – 69.99
    return "F";                   // < 60
}

// គណនា Total, Average, Grade
$total   = array_sum($scores);
$average = $total / count($scores);
$grade   = getGrade($average);

// បង្ហាញជា Table
echo "<table border='1'>";
echo "<tr><th>#</th><th>Subject</th><th>Score</th></tr>";
foreach ($scores as $i => $score) {
    $no = $i + 1;
    echo "<tr><td>$no</td><td>{$subjects[$i]}</td><td>$score</td></tr>";
}
echo "</table>";

echo "<p>Total   = $total</p>";
echo "<p>Average = " . number_format($average, 2) . "</p>";
echo "<p>Grade   = $grade</p>";
?>

<?php
// Practical 3: Multi-Students — Multidimensional Array + nested foreach
$students = [
    ["name"=>"Sophal",  "subjects"=>["C++"=>["test"=>40,"final"=>35], "C#"=>["test"=>38,"final"=>37],
                                     "PHP"=>["test"=>35,"final"=>40], "DBMS"=>["test"=>33,"final"=>32]]],
    ["name"=>"Samnang", "subjects"=>["C++"=>["test"=>35,"final"=>30], "C#"=>["test"=>40,"final"=>35],
                                     "PHP"=>["test"=>30,"final"=>35], "DBMS"=>["test"=>28,"final"=>32]]],
    ["name"=>"Chhun",   "subjects"=>["C++"=>["test"=>35,"final"=>35], "C#"=>["test"=>40,"final"=>30],
                                     "PHP"=>["test"=>35,"final"=>30], "DBMS"=>["test"=>30,"final"=>35]]],
    ["name"=>"Pheak",   "subjects"=>["C++"=>["test"=>30,"final"=>30], "C#"=>["test"=>35,"final"=>30],
                                     "PHP"=>["test"=>30,"final"=>35], "DBMS"=>["test"=>28,"final"=>32]]],
    ["name"=>"Davin",   "subjects"=>["C++"=>["test"=>38,"final"=>37], "C#"=>["test"=>30,"final"=>35],
                                     "PHP"=>["test"=>35,"final"=>35], "DBMS"=>["test"=>28,"final"=>32]]],
];
$subjectList = ["C++", "C#", "PHP", "DBMS"];

echo "<table border='1'>";
echo "<tr><th>#</th><th>Name</th>";
foreach ($subjectList as $subj) {
    echo "<th>$subj Test</th><th>$subj Final</th>";
}
echo "<th>Total</th></tr>";

foreach ($students as $i => $student) {
    $total = 0;
    echo "<tr><td>" . ($i + 1) . "</td>";
    echo "<td>{$student['name']}</td>";
    foreach ($student['subjects'] as $marks) {
        echo "<td>{$marks['test']}</td>";
        echo "<td>{$marks['final']}</td>";
        $total += $marks['test'] + $marks['final'];
    }
    echo "<td><strong>$total</strong></td></tr>";
}
echo "</table>";
?>