====== The Quiz App Version 2 ====== At this point, you should have a basic, working quiz that is pulling questions from a database. If not, take a look at [[The Quiz App]] to get started. This is what your code should look like before we get started, make sure you understand each line (and that it works). Look at the Troubleshooting section below if you run into problems.




Quiz

You answered '$user_answer' for Question #$question_id";

   if($user_answer == $questions[$question_id]['answer']) {
      echo "Correct :)";
   } else {
      echo "Wrong :(";
   }

}

?>

Question: 






Another random question

===== Sessions ===== You can store information in a session, which can be accessed on each page load. We'll use a session now to track which questions have already been answered, and we can record the name of person taking the quiz for a future high score table. You can access what is in a session array in the same way you can see what is in a request array:


print_r($_SESSION);

Let's understand sessions first, separate from the quiz code. Create a new test page and call it ''testsession.php'':





Welcome ".htmlentities($_SESSION['visitor_name'])."";
}


?>

The above code has an error in it. See if you can spot where. I'll talk people through it. I'll add to this page as we go through on the night. Some functions we'll need: phpinfo(); ===== Troubleshooting ===== ====I just get a blank white screen or HTTP ERROR 500 ==== Add some error reporting to the very top of your code:


error_reporting(E_ALL);
ini_set("display_errors", 1);

Remember to also add to any other files you might be including [or require()'ing] ====I'm getting an ''Uncaught PDOException: SQLSTATE[HY000] [1045] Access denied'' error==== Make sure you are using the correct credentials in ''questions_from_db.php''. If you are unsure, you can set them again by connecting to your mysql server on the terminal:


sudo mysql -u root

Then, inside the mysql client, create a user called ‘coding_username’, with the password ‘cheese’ and give it access to the newly created ‘coding’ database:


grant all on coding.* to coding_username@localhost identified by 'cheese';
quit

Notice we use 'coding_username' - make sure that is what is in your ''questions_from_db.php'' file. ==== Uncaught Error: Call to a member function fetchAll() on boolean ==== Make sure you have questions in your quiz_questions table (login with Adminer to check) ====== Quiz App with Session Management ======



Quiz

        Welcome to the quiz, enter a name to begin:
        
        
        
        
        You answered '$user_answer' for Question #$question_id";

   if($user_answer == $questions[$question_id]['answer']) {
        echo "Correct :)";
        $_SESSION[$player_name]['correct'][$question_id] = $question_id;
   } else {
        echo "Wrong :(";
        $_SESSION[$player_name]['wrong'][$question_id] = $question_id;
   }

}


$correct_answers = $wrong_answers = 0;
if(!empty($_SESSION[$player_name])) {
        if(!empty($_SESSION[$player_name]['correct']))
        $correct_answers = sizeof($_SESSION[$player_name]['correct']);
        if(!empty($_SESSION[$player_name]['wrong']))
        $wrong_answers = sizeof($_SESSION[$player_name]['wrong']);
        if(!empty($_SESSION[$player_name]['correct'])) {
                foreach($_SESSION[$player_name]['correct'] as $question_id) {
                        unset($questions[$question_id]);
                }
        }
        if(!empty($_SESSION[$player_name]['wrong'])) {
                foreach($_SESSION[$player_name]['wrong'] as $question_id) {
                        unset($questions[$question_id]);
                }

        }
}

$total_answered = $correct_answers + $wrong_answers;

echo "You've answered $total_answered questions.  $correct_answers right, $wrong_answers wrong.";


$available_questions = $number_of_questions - $total_answered;
?>

Welcome 
Logout
 0) {
        $random_question_id = array_rand($questions);
?>

Question: 






Another random question

        You've answered all the questions!  Your score was  out of !
prepare($sql);
                if($insert_stmt->execute([$player_name, $correct_answers, $wrong_answers])) {
                        echo "Highscore saved!";
                } else {
                        echo "Error saving highscore";
                        echo print_r($insert_stmt->errorInfo());
                }
        } else {
                echo "High score already saved.";
        }

}
?>