Question 40490 in PHP Question posted in
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Problem with PHP code(operations on variables)

This is fragment of my code:

<?php
    session_start();
    $_SESSION['counter']=0;
    if(isset($_POST['id'])){
        $id = $_POST['id'];
        $id = strval($id);
        @$_SESSION['order'] +=',';
        @$_SESSION['order'] +=strval($id);
        echo $_SESSION['order'];
        $_SESSION['counter']+=1;
    }
    echo  '<br>'.$_SESSION['counter'];
?>

and when I open up the page, I see this error

"Fatal error: Uncaught TypeError: Unsupported operand types: null +
string in C:xampphtdocspizzaindex.php:7 Stack trace: #0 {main}
thrown in C:xampphtdocspizzaindex.php on line 7"

Please help me repair this quickly, because I have to hand my project on until March 1st.

This code should import the data from $_POST['id'] to $id and add this to $_SESSION['order'] with the "," character. I tried to parse $id to string, but it seems like, it doesn’t work.

Tags:

2

Answers


  1. 0

    Adding a null value to a string value doesn’t work in php, so check the value of $_SESSION[‘order’] if it is null or not. And, += is used for arithmetic operations and not to concatenate

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  2. 0 
    session_start();
$_SESSION['counter'] = 0;

if(isset($_POST['id'])) {
    $id = strval($_POST['id']);
    if(!isset($_SESSION['order'])) {
        $_SESSION['order'] = '';
    }
    if($_SESSION['order'] != '') {
        $_SESSION['order'] .= ',';
    }
    $_SESSION['order'] .= $id;
    echo $_SESSION['order'];
    $_SESSION['counter'] += 1;
}
echo '<br>' . $_SESSION['counter'];

    In this code, we first convert $_POST[‘id’] to a string using strval(). Then we check if $_SESSION[‘order’] exists and initialize it as an empty string if it doesn’t. We also add a comma separator only if $_SESSION[‘order’] is not empty. Then we concatenate $id to $_SESSION[‘order’] using the "." operator. Finally, we increment $_SESSION[‘counter’] and display it along with the updated $_SESSION[‘order’].

    Note that it’s always a good practice to sanitize and validate user input to prevent security issues.

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