Question

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PHP: “Notice: Undefined variable” and “Notice: Undefined index”

im trying to create a simple login and register page and i am getting these errors on my index .php page,why is my index undefined these are the errors i am getting

Notice: Undefined index: username in C:\xampp\htdocs\mysite\forum part two\index.php on line 7

Notice: Undefined index: password in C:\xampp\htdocs\mysite\forum part two\index.php on line 8

the codes on line 7 and 8 these respectively

$username = $_SESSION['username'];
$password = $_SESSION['password'];

this is my index page

<?php
//This will start a session
session_start();

$username = $_SESSION['username'];
$password = $_SESSION['password'];

//Check do we have username and password
if(!$username && !$password){
echo "Welcome Guest! <br> <a href=login.php>Login</a> | <a href=register.php>Register</a>";
}else{
echo "Welcome ".$username." (<a href=logout.php>Logout</a>)";
}
?> 

Answer 1

You are getting those errors because your session has not been declared earlier,So you need to check if your session is declared earlier. you can use php empty or isset function

<?php
//This will start a session
session_start();
$username ='';$password ='';
if(!empty($_SESSION['username']))//check if it is defined
    $username = $_SESSION['username'];

if(!empty($_SESSION['password']))//check if it is defined
    $password = $_SESSION['password'];

//Check do we have username and password
if($username=='' && $password==''){
   echo "Welcome Guest! <br> <a href=login.php>Login</a> | <a href=register.php>Register</a>";
}else{
echo "Welcome ".$username." (<a href=logout.php>Logout</a>)";
}
?>