Checkbox error when false. [duplicate]

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• PHP: “Notice: Undefined variable” and “Notice: Undefined index” 11 answers

Im getting errors when my checkboxes remains unchecked. The error message is: Notice: Undefined index: answer_1 in C:\MAMP\htdocs\webutvikling\query.php on line 121

which is where the $value variable is:

for ($i=0; $i < $steg; $i++) {
                $value = $_POST["answer_$i"];
                        echo " <input type='hidden' name='answer_$i' id='answer_$i' value='$value' />\n";
        }

When the checkboxes is checked, there is no error at all. I have added some comments further down below that might help.

<?php
//Questionsarray

    $questions = array(
        array(
            'text' => 'Hva heter du?',
            'type' => 'text',
        ),
        array(
            'text' => 'Er du cool?',
            'type' => 'checkbox',
        ),
        array(
            'text' => 'Hvor gammel er du?',
            'type' => 'text',
        ),
        array(
            'text' => 'Er du awesome?',
            'type' => 'checkbox',
        ),
        array(
            'text' => 'Bor du i Santa Monica?',
            'type' => 'checkbox',
        )
    );

       $steg = isset($_POST['step']) ? $_POST['step'] : 0;

        $spm_teller = count($questions);

        $submitted = isset($_POST['step']) ? true : false;



        if ($submitted) {
                if (isset($_POST ['next'])) {
                        $steg = $_POST['step'] + 1;
                } else {
                        $steg = $_POST['step'] - 1;
                }
        }

        echo "<p> <a href='{$_SERVER['PHP_SELF']}'> Start på nytt </a> </p> \n";

        if ($steg >= $spm_teller ) {
                echo "<p> Ferdig </p>";

//Giving values to the checkbox when checked/unchecked

        foreach ($questions as $key => $questions) {
                        if ( $questions['type'] == 'checkbox' ) {  
                                if (isset($_POST["answer_$key"])){
                                         $_POST["answer_$key"] = "Ja!";
                                } else {
                                        $_POST["answer_$key"] = "Nei!";
                                }
                        }
                echo $questions['text'] . ': ' . $_POST["answer_$key"] . "<br>\n";    

        }


        } else {
                echo " <p> Du er nå på steg nr: $steg </p>";
                echo " <form target='' method='post'>\n";
                echo " <input type ='hidden' name='step' id='step' value='$steg' />\n";



       //Echoing questions

        echo $questions[$steg]['text'] . " <br />\n";
        if (!empty($_POST["answer_$steg"])) {
                $value = ($_POST["answer_$steg"]);
        } else {
                $value = '';
        }

        //Checking if the checkbox is true or false. Im thinking maybe the error is here? When I check the checkboxes I get no errors, but when it remains unchecked i get the error code: Notice: Undefined index: answer_1 in C:\MAMP\htdocs\webutvikling\query on line 121

        if ($questions[$steg]['type'] == 'checkbox') {
                if ($value == 'on' ) {
                        $selected = ' checked="checked"' ;
                } if ($value == '') {
                        $selected = '';
                }
                echo "<input type = 'checkbox' name='answer_$steg' id='answer_$steg' $selected />\n";
        } else {
                echo "<input type = 'text' name='answer_$steg' id='answer_$steg' value='$value' />\n";
        }

     //Stores all the answers and puts it in the $value variable

        for ($i=0; $i < $steg; $i++) {
                $value = $_POST["answer_$i"];
                        echo " <input type='hidden' name='answer_$i' id='answer_$i' value='$value' />\n";
        }

        echo "</form> \n ";
}      



?>
</body>
</html>