This code is giving med problem. It dos not stop when the last question has been answered. It just give me this error:

Warning: Undefined array key 2 in /customers/5/8/b/kbekker.dk/httpd.www/Fag/Dansk/Opgaver/Ordklasser/find_navneord_001.php on line 71 Warning: Trying to access array offset on value of type null in /customers/5/8/b/kbekker.dk/httpd.www/Fag/Dansk/Opgaver/Ordklasser/find_navneord_001.php on line 71 3

which is refering to line:

 <label for="question"><?php echo ($currentQuestion+1).". ". $questionsAndAnwsers[$currentQuestion]["question"];?></label>

I am a noob at php.

I have try to put a loop outside of it, but that dos not help either.

<?php
// Declare all your questions and answers as multi dimensional array
$questionsAndAnwsers = array(array("question" => "1. How many sides does a triangle have?", "answer" => "three"),
                            array("question" => "2. How many sides does a square have?", "answer" => "four"));
      
// current question
$currentQuestion = 0;
if(isset($_POST["currentQuestion"])){
    $currentQuestion = $_POST["currentQuestion"];
    if($_POST["guess"] == $questionsAndAnwsers[$currentQuestion]["answer"]){
        // answer was correct, increment your question-counter for the next question
        $currentQuestion++;
        // print success message
        echo "Det var rigtigt";
    } else {
        // question was wrong, counter stays as it is, so same question will be printed
        // print failure message
        echo "prøv igen";
    }
}
?>
<form method="POST" action="">
    <label for="question"><?php echo ($currentQuestion+1).". ". $questionsAndAnwsers[$currentQuestion]["question"];?></label>
    <input type="hidden" name="currentQuestion" value="<?php echo $currentQuestion;?>">
    <input type="text" name="guess" value="">
    <input type="submit">
</form>