Starting and using sessions in PHP - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start a session in PHP.

PHP

<?php
[1];
?>

Drag options to blanks, or click blank then click option'

Astart_session()

Bsession_start()

Cbegin_session()

Dsession_begin()

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect function names like start_session() or session_begin()

Forgetting the parentheses after the function name

In PHP, session_start() is used to start a new session or resume an existing one.

2fill in blank

medium

Complete the code to set a session variable named 'user' with value 'Alice'.

PHP

<?php
session_start();
$_SESSION[[1]] = 'Alice';
?>

Drag options to blanks, or click blank then click option'

A'user'

B'username'

C'name'

D'id'

Attempts:

3 left

💡 Hint

Common Mistakes

Using keys like 'username' or 'name' instead of 'user'

Forgetting quotes around the key

The session variable key should be 'user' to match the requirement.

3fill in blank

hard

Fix the error in the code to correctly start a session and set a variable.

PHP

<?php
[1];
$_SESSION['count'] = 1;
?>

Drag options to blanks, or click blank then click option'

Astart_session()

Bbegin_session()

Csession_begin()

Dsession_start()

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect function names

Missing parentheses

The correct function to start a session is session_start(). Other options are invalid.

4fill in blank

hard

Fill both blanks to check if a session variable 'logged_in' is set and true.

PHP

<?php
session_start();
if (isset($_SESSION[1]) && $_SESSION[2] === true) {
    echo 'User is logged in';
}
?>

Drag options to blanks, or click blank then click option'

A['logged_in']

B['login']

D['user']

Attempts:

3 left

💡 Hint

Common Mistakes

Using different keys in the two blanks

Using keys like 'login' or 'user' instead of 'logged_in'

To check the session variable 'logged_in', use ['logged_in'] in both places.

5fill in blank

hard

Fill all three blanks to start a session, set 'role' to 'admin', and then print it.

PHP

<?php
[1];
$_SESSION[2] = 'admin';
echo $_SESSION[3];
?>

Drag options to blanks, or click blank then click option'

Asession_start()

B['role']

Dsession_begin()

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong function to start session

Using different keys for setting and printing

Forgetting quotes around the key

Start the session with session_start(), then use the key 'role' in square brackets to set and print the session variable.

Practice

1. What is the main purpose of using session_start() in PHP?

easy

A. To begin a session and enable storing data across pages

B. To end a session and clear all session data

C. To connect to a database for user authentication

D. To send cookies to the user's browser

Solution

1. Step 1: Understand what session_start() does

   This function initializes a session or resumes the current one based on a session identifier passed via a cookie or URL.

2. Step 2: Recognize session purpose

   Sessions allow data to be saved and accessed across multiple pages for the same user, such as login status or preferences.

3. Final Answer:

   To begin a session and enable storing data across pages -> Option A

4. Quick Check:

   session_start() starts session = D [OK]

Hint: Remember: session_start() must run before any output [OK]

Common Mistakes:

• Thinking session_start() ends a session
• Confusing sessions with database connections
• Calling session_start() after HTML output

2. Which of the following is the correct way to start a session in PHP?

easy

A. session.begin();

B. start_session();

C. session_start();

D. begin_session();

Solution

1. Step 1: Recall PHP session function syntax

   The correct function to start a session is session_start() with an underscore and parentheses.

2. Step 2: Check other options for syntax errors

   Options B, C, and D are not valid PHP functions and will cause errors.

3. Final Answer:

   session_start(); -> Option C

4. Quick Check:

   Correct PHP session start syntax = A [OK]

Hint: Use exact function name: session_start() [OK]

Common Mistakes:

• Using wrong function names like start_session()
• Missing parentheses after session_start
• Using camelCase instead of underscore

3. What will be the output of this PHP code?

<?php
session_start();
$_SESSION['user'] = 'Alice';
echo $_SESSION['user'];
?>

medium

A. user

B. Alice

C. Array

D. Undefined index error

Solution

1. Step 1: Start session and assign value

   The code starts a session and sets the session variable 'user' to 'Alice'.

2. Step 2: Output the session variable

   Using echo $_SESSION['user']; prints the value stored, which is 'Alice'.

3. Final Answer:

   Alice -> Option B

4. Quick Check:

   $_SESSION['user'] = 'Alice' outputs Alice [OK]

Hint: Session variables store values like arrays [OK]

Common Mistakes:

• Expecting 'user' instead of its value
• Forgetting to call session_start() first
• Confusing session variables with regular variables

4. Identify the error in this PHP code snippet:

<?php
$_SESSION['count'] = 1;
echo $_SESSION['count'];
?>

medium

A. Cannot echo session variables

B. Incorrect variable name $_SESSION

C. Session variables must be integers only

D. Missing session_start() before using $_SESSION

Solution

1. Step 1: Check session initialization

   The code uses $_SESSION but never calls session_start() to begin the session.

2. Step 2: Understand session usage rules

   Without calling session_start(), PHP does not know which session to use, causing errors or empty values.

3. Final Answer:

   Missing session_start() before using $_SESSION -> Option D

4. Quick Check:

   Always call session_start() before $_SESSION [OK]

Hint: Always start session before accessing $_SESSION [OK]

Common Mistakes:

• Using $_SESSION without session_start()
• Assuming $_SESSION works like normal variables
• Trying to echo $_SESSION without initialization

5. You want to count how many times a user visits a page using sessions. Which code correctly increments the visit count each time the page loads?

<?php
// Fill in the missing part

if (isset($_SESSION['visits'])) {
    $_SESSION['visits']++;
} else {
    $_SESSION['visits'] = 1;
}
echo "Visit number: " . $_SESSION['visits'];
?>

hard

A. session_start();

B. session_destroy();

C. session_unset();

D. session_write_close();

Solution

1. Step 1: Recognize session must be started

   To use $_SESSION variables, the session must be started with session_start(); at the top.

2. Step 2: Understand the code logic

   The code checks if 'visits' exists in the session, increments it if yes, or sets it to 1 if no, then prints the count.

3. Final Answer:

   session_start(); -> Option A

4. Quick Check:

   Start session before using $_SESSION to track visits [OK]

Hint: Always call session_start() before session variables [OK]

Common Mistakes:

• Forgetting session_start() causes no session data
• Using session_destroy() resets visits
• Confusing session_unset() with starting session