6-MARKS

1. Explain sending data to web browser with example.

Ans: Sending data to the web browser using PHP involves outputting
content that the browser can interpret and display. Common functions
for this purpose include print, echo, and other output functions. Here
are examples of each:

• Using echo
The echo function is commonly used to output one or more strings to
the browser. It does not return any value.
Ex:
<?php
echo "Hello, World!";
echo "This is a test.";
?>

• Using print
The print function is similar to echo, but it returns 1, so it can be used
in expressions.
Ex:
<?php
print "Hello, World!";
print "This is a test.";
?>
 • Using print_r
The print_r function is useful for printing human-readable information
about a variable, especially arrays and objects.
Ex:
<?php
$array = array("apple", "banana", "cherry");
print_r($array);
?>

• Using printf
The printf function outputs a formatted string.
Ex:
<?php
$number = 10;
$string = "Hello";
printf("The number is %d and the string is %s", $number, $string);
?>

• Using sprintf
The sprintf function works like printf, but it returns the formatted string
instead of printing it.
Ex:
<?php
$number = 10;
$string = "Hello";
$result = sprintf("The number is %d and the string is %s", $number,
$string);
echo $result;
?>

2. Explain do while loop with example.

Ans: A do...while loop in PHP executes a block of code at least once
and then repeatedly executes the block as long as a specified condition
is true. The key difference between a do...while loop and a while loop
is that the do...while loop guarantees the code block runs at least once,
regardless of the condition.

Syntax for a do...while loop:

php
do {
// Code to be executed
} while (condition);

Example:
Let's create an example where we print numbers from 1 to 5 using a
do...while loop.

php
<?php
$number = 1;
do {
echo "The number is: $number\n";
 $number++;
} while ($number <= 5);
?>

Output:
The output of the above example would be:
The number is: 1
The number is: 2
The number is: 3
The number is: 4
The number is: 5
This example demonstrates how the do...while loop ensures the code
inside the do block runs at least once before checking the condition.

3. Write a note on include and require function with example.

Ans: In PHP, the include and require statements are used to include
and evaluate files. The main difference between them is how they
handle errors.

• Include:
The include statement includes and evaluates the specified file. If the
file is not found, a warning is issued, but the script continues to execute.
Syntax:
php
include 'filename.php';
Example:
php
// main.php
echo "This is the main file.<br>";
include 'included_file.php';
echo "Back to the main file.<br>";

php
// included_file.php
echo "This is the included file.<br>";

Output:
This is the main file.
This is the included file.
Back to the main file.

• Require:
The require statement includes and evaluates the specified file. If the
file is not found, a fatal error is issued, and the script stops executing.

Syntax:
php
require 'filename.php';
Example:
php
// main.php
echo "This is the main file.<br>";
require 'required_file.php';
echo "Back to the main file.<br>";
php
// required_file.php
echo "This is the required file.<br>";

Output:
This is the main file.
This is the required file.
Back to the main file.

4. Explain formal vs actual parameters?

Ans: In PHP, formal parameters and actual parameters refer to the
parameters used in functions, but they are used in different contexts:

1. Formal Parameters:
• These are the parameters listed in the function declaration.
• They act as placeholders for the values that will be passed to the
function when it is called.
Example:
php
function add($a, $b) {
 return $a + $b;
}
Here, $a and $b are formal parameters.

2. Actual Parameters:
• These are the real values or arguments passed to the function
when it is called.
• They are assigned to the corresponding formal parameters in
the function.
Example:
php
$result = add(2, 3);
Here, 2 and 3 are actual parameters.
When the function add is called with 2 and 3, these values are assigned
to the formal parameters $a and $b, respectively, and the function
executes using these values.
5. Explain creating and declaring a string with example.
Ans: In PHP, a string is a sequence of characters enclosed within
quotes. You can declare and create a string using either single quotes ('
') or double quotes (" "). Here are examples of both:

• Using Single Quotes:

When you use single quotes, the string is taken literally, and variable
names or escape sequences are not interpreted.
Ex:
php
<?php
$string1 = 'Hello, World!';
echo $string1; // Outputs: Hello, World!
?>

• Using Double Quotes:

When you use double quotes, PHP will interpret variables and some
escape sequences within the string.
Ex:
php
<?php
$name = "John";
$string2 = "Hello, $name!";
echo $string2; // Outputs: Hello, John!
?>

• Concatenating Strings:
You can also concatenate strings using the dot (.) operator.
Ex:
php
<?php
$greeting = "Hello";
$name = "Jane";
$combined = $greeting . ", " . $name . "!";
echo $combined; // Outputs: Hello, Jane!
?>
 • Escaping Characters:
If you need to include a single quote or double quote within a string,
you can escape them with a backslash (\).
Ex:
php
<?php
$string3 = 'It\'s a beautiful day!';
$string4 = "He said, \"Hello, World!\"";
echo $string3; // Outputs: It's a beautiful day!
echo $string4; // Outputs: He said, "Hello, World!"
?>

6. Write a note on constructor and destructor with an example.

Ans: In PHP, constructors and destructors are special methods used to
initialize and clean up objects, respectively.

• Constructor:
A constructor is a method that is automatically called when an object
of a class is created. It is typically used to initialize properties or
perform setup operations. In PHP, the constructor method is named
__construct.

• Destructor:
A destructor is a method that is automatically called when an object is
destroyed. It is used to perform cleanup operations, such as releasing
resources or closing connections. In PHP, the destructor method is
named __destruct.
Example:
Here’s an example of a class in PHP that uses a constructor and a
destructor:
php
<?php
class MyClass {
private $name;
public function __construct($name) {
$this->name = $name;
echo "Constructor: Object is created with name {$this-
>name}.\n";
}
public function __destruct() {
echo "Destructor: Object with name {$this->name} is
destroyed.\n";
}
public function display() {
echo "The name is {$this->name}.\n";
}
}
$obj = new MyClass("John Doe");
$obj->display();
?>
Explanation:
1. Constructor: The __construct method takes a parameter $name and
initializes the property $name of the class. It also prints a message
indicating that the object is created.

2. Destructor: The __destruct method prints a message indicating that

the object is destroyed. This method is automatically called when the
script ends or the object is no longer referenced.

3. Usage: When an object of MyClass is created with the name "John

Doe", the constructor initializes the object and prints the message. The
display method shows the name. When the script ends, the destructor
is called, and it prints the message indicating the object is destroyed.

7. Explain html form handling with example.

Ans: HTML form handling in PHP involves creating an HTML form
that collects user input and then processing that input on the server side
using PHP. Here's a step-by-step example to illustrate the process:
Step 1: Create an HTML Form
Create an HTML form that collects user input. In this example, we'll
create a simple form that collects a user's name and email address.
Ex:
html
<!DOCTYPE html>
<html>
<head>
<title>HTML Form Example</title>
</head>
<body>
<form action="process_form.php" method="post">
<label for="name">Name:</label>
<input type="text" id="name" name="name"><br><br>
<label for="email">Email:</label>
<input type="text" id="email" name="email"><br><br>
<input type="submit" value="Submit">
</form>
</body>
</html>

Step 2: Handle the Form Submission in PHP

Create a PHP script (process_form.php) to handle the form submission.
This script will process the data submitted by the form and display it.
Ex:
php
<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
$name = htmlspecialchars($_POST['name']);
$email = htmlspecialchars($_POST['email']);
echo "Name: " . $name . "<br>";
echo "Email: " . $email . "<br>";
}
?>
Explanation:
1. HTML Form:
• The form element has two important attributes: action and
method.
• action: Specifies the URL of the PHP script that will process the
form data. In this case, it's process_form.php.
• method: Specifies the HTTP method to use when sending form
data. The post method is used here for more secure data handling.

2. PHP Script:
• The script checks if the request method is POST to ensure that
the form has been submitted.
• The $_POST superglobal array is used to collect form data.
• The htmlspecialchars function is used to sanitize the input data
to prevent XSS (Cross-Site Scripting) attacks.
• The collected and sanitized data is then displayed.

8. Explain accessing of my SQL client using php admin

Ans: To access your MySQL database using phpMyAdmin, follow
these steps:
1. Install phpMyAdmin:
• If phpMyAdmin is not already installed, download it from the
official[phpMyAdminwebsite](https://www.phpmyadmin.net/
).
• Follow the installation instructions, which usually involve
placing the phpMyAdmin folder in your web server's
document root (e.g., /var/www/html for Apache).
2. Configure phpMyAdmin:
• Edit the config.inc.php file in the phpMyAdmin directory to
configure your phpMyAdmin setup. You'll need to specify your
MySQL server details, such as host, user, and password.

3. Access phpMyAdmin:
• Open a web browser and navigate to the phpMyAdmin URL.
This is typically http://localhost/phpmyadmin or http://your-
server-ip/phpmyadmin if you're accessing it remotely.
• You should see the phpMyAdmin login screen.

4. Login to phpMyAdmin:
• Enter your MySQL username and password to log in. If you
don't have a MySQL user account, you'll need to create one
using MySQL command-line or another MySQL management
tool.

5. Using phpMyAdmin:
• Once logged in, you'll see the phpMyAdmin interface, where
you can manage your MySQL databases. This includes
creating, modifying, and deleting databases and tables,
running SQL queries, importing/exporting data, and more.

9. Explain how to connect MYSQL and select database.

Ans: To connect to a MySQL database and select a database in PHP,
you can use the mysqli extension, which provides a way to interact with
MySQL databases. Below are the steps and sample code to achieve this:
1. Connect to MySQL Server.
2. Select Database.
3. Check Connection.
4. Close the Connection.

Here's a complete example:

php
<?php
$servername = "localhost";
$username = "your_username";
$password = "your_password";
$dbname = "your_database";
$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
echo "Connected successfully";
$conn->close();
?>

Detailed Steps:

1. Database Credentials:
• $servername: The hostname of the MySQL server (usually
localhost if running on the same server).
 • $username: The MySQL username.
• $password: The password for the MySQL user.
• $dbname: The name of the database you want to connect to.

2. Create a Connection:
php
$conn = new mysqli($servername, $username, $password,
$dbname);
This line creates a new mysqli object and attempts to connect to the
MySQL server using the provided credentials.

3. Check Connection:
php
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
echo "Connected successfully";
This checks if the connection was successful. If there is an error, it
will stop the script and print the error message.

4. Close the Connection:

php
$conn->close();
This closes the connection to the database when you are done.
 10. Explain data types in PHP with example.
Ans: PHP, like many programming languages, has several data types
that are used to hold different kinds of values. Here are the main data
types in PHP are:
1. The predefined data types are:

• Integer: A whole number without a decimal point.

Ex:
php
$intVar = 123;
echo $intVar; // Output: 123

• Float (Double): A number with a decimal point or a number in

exponential form.
Ex:
php
$floatVar = 123.45;
echo $floatVar; // Output: 123.45

• String: A sequence of characters.

Ex:
php
$stringVar = "Hello, World!";
echo $stringVar; // Output: Hello, World!
• Boolean: Represents two possible states: true or false.
Ex:
php
$boolVar = true;
echo $boolVar; // Output: 1 (true is represented as 1, false as empty)

2. The user-defined (compound) data types are:

• Array: An ordered map that holds multiple values, which can be

of different data types.
Ex:
php
$arrayVar = array("apple", "banana", "cherry");
echo $arrayVar[1]; // Output: banana

• Object: An instance of a class. Classes are blueprints for objects.

Ex:
php
class Car {
public $color;
public $model;
public function __construct($color, $model) {
$this->color = $color;
$this->model = $model;
}
 public function message() {
return "My car is a " . $this->color . " " . $this->model . ".";
}
}
$myCar = new Car("black", "Volvo");
echo $myCar->message(); // Output: My car is a black Volvo.

3. The special data types are:

• NULL: A special data type that only has one value: NULL.
Ex:
php
$nullVar = NULL;
echo $nullVar; // Output: (an empty string)

• Resource: A special variable, holding a reference to an external

resource (such as a database connection).
Ex:
php
$file = fopen("test.txt", "r");
echo $file; // Output: Resource id #3
 11. Explain while loop in with example.
Ans: A while loop in PHP is used to execute a block of code repeatedly
as long as a specified condition is true. The condition is evaluated
before each iteration of the loop, and if the condition evaluates to true,
the code block inside the loop is executed. This process continues until
the condition evaluates to false.

Syntax for a while loop:

php
while (condition) {
// code to be executed
}

Example:
php
<?php
$count = 1;
while ($count <= 5) {
echo "Count: $count\n";
$count++;
}
?>
Explanation:
1. Initialization: The variable $count is initialized to 1.
2. Condition: The condition $count <= 5 is checked. If it is true, the
code inside the loop is executed.
3. Execution: The string "Count: $count" is printed, where $count is the
current value of the variable.
4. Increment: The variable $count is incremented by 1 using $count++.
5. Revaluation: The condition $count <= 5 is re-evaluated, and steps 3
and 4 are repeated until the condition becomes false.

Output:
Count: 1
Count: 2
Count: 3
Count: 4
Count: 5

12. Write a note on array with an example (index and associative).

Ans: An array in PHP is a data structure that allows you to store
multiple values in a single variable. There are two main types of arrays
in PHP: indexed arrays and associative arrays.

1. Indexed Arrays
An indexed array is an array with numeric indices. These indices are
automatically assigned starting from 0.
Example:
php
<?php
$fruits = array("Apple", "Banana", "Orange");
echo $fruits[0]; // Outputs: Apple
echo $fruits[1]; // Outputs: Banana
echo $fruits[2]; // Outputs: Orange
$fruits[] = "Grapes";
foreach ($fruits as $fruit) {
echo $fruit . " ";
}
?>

2. Associative Arrays
An associative array uses named keys that you assign to them. This type
of array is useful for storing pairs of keys and values.
Example:
php
<?php
$person = array(
"first_name" => "John",
"last_name" => "Doe",
"age" => 30
);
echo $person["first_name"]; // Outputs: John
echo $person["last_name"]; // Outputs: Doe
echo $person["age"]; // Outputs: 30
$person["occupation"] = "Developer";
foreach ($person as $key => $value) {
echo $key . ": " . $value . " ";
}
?>

13. Explain date and time function with an example in php.

Ans: PHP provides a wide array of functions for handling dates and
times. One of the most commonly used functions is date(), which
formats a local date and time, and strtotime(), which parses an English
textual datetime description into a Unix timestamp.

1. Date() function:
The date() function formats a local date and time, and it takes at least
one parameter: a format string that defines the format of the output.
Ex:
php
<?php
date_default_timezone_set('America/New_York');
$currentDate = date('Y-m-d H:i:s');
echo "The current date and time is: " . $currentDate;
?>
In this example:
• date_default_timezone_set('America/New_York'); sets the
default timezone to New York.
• date('Y-m-d H:i:s'); gets the current date and time in the format
YYYY-MM-DD HH:MM:SS.

2. Strtotime() function:
The strtotime() function converts an English textual datetime
description into a Unix timestamp. This can be very useful for
manipulating dates.
Ex:
php
<?php
$currentTimestamp = time();
$nextWeekTimestamp = strtotime('+1 week');
$currentDate = date('Y-m-d H:i:s', $currentTimestamp);
$nextWeekDate = date('Y-m-d H:i:s', $nextWeekTimestamp);
echo "Current date and time: " . $currentDate . "\n";
echo "Date and time next week: " . $nextWeekDate;
?>

In this example:
• time() gets the current Unix timestamp.
• strtotime('+1 week') gets the Unix timestamp for the date and time
one week from now.
• date('Y-m-d H:i:s', $currentTimestamp); formats the current
timestamp to a readable date.
 • date('Y-m-d H:i:s', $nextWeekTimestamp); formats the next week
timestamp to a readable date.

14. Explain working with database with example (create,

select,execute) in php.
Ans: Working with a database in PHP involves several steps:
connecting to the database, creating tables, inserting data, retrieving
data, and sometimes updating or deleting data. Below is a basic
example using MySQL as the database.

Step 1: Database Connection

First, you need to establish a connection to the database using the
mysqli or PDO extension.
Ex:
php
<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";
$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
echo "Connected successfully";
?>
Step 2: Creating a Table
Once connected, you can create a table. Here is an example:
Ex:
php
<?php
$sql = "CREATE TABLE MyGuests (
id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
firstname VARCHAR(30) NOT NULL,
lastname VARCHAR(30) NOT NULL,
email VARCHAR(50),
reg_date TIMESTAMP
)";
if ($conn->query($sql) === TRUE) {
echo "Table MyGuests created successfully";
} else {
echo "Error creating table: " . $conn->error;
}
?>

Step 3: Inserting Data

To insert data into the table:
Ex:
php
<?php
$sql = "INSERT INTO MyGuests (firstname, lastname, email)
VALUES ('John', 'Doe', 'john@example.com')";
if ($conn->query($sql) === TRUE) {
echo "New record created successfully";
} else {
echo "Error: " . $sql . "<br>" . $conn->error;
}
?>

Step 4: Selecting Data

To retrieve data from the table:
Ex:
php
<?php
$sql = "SELECT id, firstname, lastname FROM MyGuests";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
while($row = $result->fetch_assoc()) {
echo "id: " . $row["id"]. " - Name: " . $row["firstname"]. " " .
$row["lastname"]. "<br>";
}
} else {
echo "0 results";
}
?>
Step 5: Closing the Connection
Finally, you should close the connection when you're done:
Ex:
php
<?php
$conn->close();
?>
Complete Example
php
<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";
$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
echo "Connected successfully";
$sql = "CREATE TABLE MyGuests (
id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
firstname VARCHAR(30) NOT NULL,
lastname VARCHAR(30) NOT NULL,
email VARCHAR(50),
reg_date TIMESTAMP
)";
if ($conn->query($sql) === TRUE) {
echo "Table MyGuests created successfully";
} else {
echo "Error creating table: " . $conn->error;
}
$sql = "INSERT INTO MyGuests (firstname, lastname, email)
VALUES ('John', 'Doe', 'john@example.com')";
if ($conn->query($sql) === TRUE) {
echo "New record created successfully";
} else {
echo "Error: " . $sql . "<br>" . $conn->error;
}
$sql = "SELECT id, firstname, lastname FROM MyGuests";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
while($row = $result->fetch_assoc()) {
echo "id: " . $row["id"]. " - Name: " . $row["firstname"]. " " .
$row["lastname"]. "<br>";
}
} else {
echo "0 results";
}
$conn->close();
?>