Category: Examples

<?php
$file = fopen("example.txt", "w");
fwrite($file, "Hello File Handling!");
fclose($file);

$file = fopen("example.txt", "r");
echo fread($file, filesize("example.txt"));
fclose($file);
?>

Explanation:

• "w" → write mode (creates/overwrites file).
• "r" → read mode.
• fwrite writes text into file, fread reads it.

<?php
$text = " Hello PHP! ";

echo strlen($text);    // 11
echo strtolower($text); // hello php!
echo strtoupper($text); // HELLO PHP!
echo trim($text);       // removes extra spaces
echo str_replace("PHP", "World", $text); // Hello World!
?>

Explanation:
PHP has many string functions for modifying and formatting text.

<?php
$day = "Monday";

switch ($day) {
case "Monday":
    echo "Start of the week!";
    break;
case "Friday":
    echo "Weekend is near!";
    break;
default:
    echo "Just another day.";
}
?>

Explanation:

• switch is an alternative to multiple if-else statements.
• If $day = "Monday", output will be Start of the week!

<?php
$conn = new mysqli("localhost", "root", "", "testdb");

if ($conn->connect_error) {
die("Connection failed: " . $conn-&gt;connect_error);
}
echo "Connected successfully!";
?>

Explanation:

• mysqli is used to connect PHP with MySQL database.
• Replace "localhost", "root", "", "testdb" with your DB credentials.

Create a file form.html:

<form method="GET" action="welcome.php">
  Name: <input type="text" name="username">
  <input type="submit">
</form>

In welcome.php:

<?php
echo "Welcome " . $_GET["username"];
?>

Explanation:

• When you submit the form, username value is sent to welcome.php.
• Example: If you type Saim, it shows Welcome Saim.

<?php
$person = [
"name" =&gt; "Ali",
"age" =&gt; 30,
"city" =&gt; "Karachi"
];

echo $person["name"]; // Ali
?>

Explanation:

• Associative arrays use key-value pairs.
• You can access values using their keys.

<?php
function greet($name) {
return "Hello, $name!";
}

echo greet("Saim");
?>

Explanation:

• Functions are created with function.
• You can pass parameters ($name).
• Output: Hello, Saim!

<?php
$fruits = ["Apple", "Banana", "Orange"];

foreach ($fruits as $fruit) {
echo $fruit . "&lt;br&gt;";
}
?>

Output:

Apple  
Banana  
Orange

<?php
$i = 1;
while ($i <= 3) {
echo "Count: $i &lt;br&gt;";
$i++;
}
?>

(a) For Loop

<?php
for ($i = 1; $i <= 5; $i++) {
echo "Number: $i &lt;br&gt;";
}
?>

Output:

Number: 1  
Number: 2  
Number: 3  
Number: 4  
Number: 5