Here is my code
<html>
<head>
<title>login page</title>
</head>
<body bgcolor="black" style="color:gray">
<form action="index.php" method=get>
<h1 align="center" style="color:gray" >Welcome to this simple application</h1>
<?php
session_start(); 
if(isset($_SESSION["logging"])&& $_SESSION["logged"])
{
     print_secure_content();
}
else {
    if(!$_SESSION["logging"])
    {  
    $_SESSION["logging"]=true;
    loginform();
    }
       else if($_SESSION["logging"])
       {
         $number_of_rows=checkpass();
         if($number_of_rows==1)
            {   
             $_SESSION[user]=$_GET[userlogin];
             $_SESSION[logged]=true;
             print"<h1>you have loged in successfully</h1>";
             print_secure_content();
            }
            else{
                print "wrong pawssword or username, please try again";  
                loginform();
            }
        }
     }
function loginform()
{
print "please enter your login information to proceed with our site";
print ("<table border='2'><tr><td>username</td><td><input type='text' name='userlogin' size'20'></td></tr><tr><td>password</td><td><input type='password' name='password' size'20'></td></tr></table>");
print "<input type='submit' >"; 
print "<h3><a href='registerform.php'>register now!</a></h3>";  
}
function checkpass()
{
$servername="localhost";
$username="root";
$conn=  mysqli_connect($servername,$username)or die(mysqli_error());
mysqli_select_db($conn,"test");
$sql="select * from users where name='$_POST[userlogin]' and password='$_POST[password]'";
$result=mysqli_query($conn,$sql) or die(mysqli_error());
return  mysqli_num_rows($result);
}
function print_secure_content()
{
    print("<b><h1>hi mr.$_SESSION[user]</h1>");
    print "<br><h2>only a logged in user can see this</h2><br><a href='logout.php'>Logout</a><br>"; 
}
?>
</form>
</body>
</html>  
I get this 3 errors
Notice: Undefined index: logged in C: on line 10 Notice: Undefined index: userlogin in C on line 51 Notice: Undefined index: password in on line 51
I have tryied isset() but nothing changed on line 10. End error 2 and 3 i have no clue. Thank you very much.
I have looked in Reference topic,but it didn't solve my problem.
 
    