Category: PHP

<?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

<?php
$marks = 75;

if ($marks >= 50) {
echo "You passed!";
} else {
echo "You failed!";
}
?>

Explanation:

• If condition is true, “You passed!” will be printed.
• Otherwise, “You failed!” is shown.

<?php
$number = 100;        // Integer
$price = 99.99;       // Float
$name = "PHP";        // String
$is_active = true;    // Boolean
?>

Explanation:
PHP supports int, float, string, boolean, array, object, null types.

<?php
$name = "Saim";
$age = 25;

echo "My name is $name and I am $age years old.";
?>

Explanation:

• Variables in PHP start with $.
• Strings inside double quotes can include variables.
• Output: My name is Saim and I am 25 years old.