CREATE TABLE users (
    username varchar(30),
    password varchar(32));

<?

/**
 * Connect to the mysql database.
 */
$conn = mysql_connect("localhost", "User_Name", "Pass") or die(mysql_error());
mysql_select_db('Database Name', $conn) or die(mysql_error());

?>

<?

/**
 * Checks whether or not the given username is in the
 * database, if so it checks if the given password is
 * the same password in the database for that user.
 * If the user doesn't exist or if the passwords don't
 * match up, it returns an error code (1 or 2).
 * On success it returns 0.
 */
function confirmUser($username, $password){
  global $conn;
  /* Add slashes if necessary (for query) */
  if(!get_magic_quotes_gpc()) {
    $username = addslashes($username);
  }

  /* Verify that user is in database */
  $q = "select password from users where username = '$username'";
  $result = mysql_query($q,$conn);
  if(!$result || (mysql_numrows($result) < 1)){
      return 1; //Indicates username failure
  }

  /* Retrieve password from result, strip slashes */
  $dbarray = mysql_fetch_array($result);
  $dbarray['password']  = stripslashes($dbarray['password']);
  $password = stripslashes($password);

  /* Validate that password is correct */
  if($password == $dbarray['password']){
      return 0; //Success! Username and password confirmed
  }
  else{
      return 2; //Indicates password failure
  }
}

/**
 * checkLogin - Checks if the user has already previously
 * logged in, and a session with the user has already been
 * established. Also checks to see if user has been remembered.
 * If so, the database is queried to make sure of the user's
 * authenticity. Returns true if the user has logged in.
 */
function checkLogin(){
  /* Check if user has been remembered */
  if(isset($_COOKIE['cookname']) && isset($_COOKIE['cookpass'])){
      $_SESSION['username'] = $_COOKIE['cookname'];
      $_SESSION['password'] = $_COOKIE['cookpass'];
  }

  /* Username and password have been set */
  if(isset($_SESSION['username']) && isset($_SESSION['password'])){
      /* Confirm that username and password are valid */
      if(confirmUser($_SESSION['username'], $_SESSION['password']) != 0){
        /* Variables are incorrect, user not logged in */
        unset($_SESSION['username']);
        unset($_SESSION['password']);
        return false;
      }
      return true;
  }
  /* User not logged in */
  else{
      return false;
  }
}

/**
 * Determines whether or not to display the login
 * form or to show the user that he is logged in
 * based on if the session variables are set.
 */
function displayLogin(){
  global $logged_in;
  if($logged_in){
      echo "<h1>Logged In!</h1>";
      echo "Welcome <b>$_SESSION[username]</b>, you are logged in. <a href=\"logout.php\">Logout</a>";
  }
  else{
?>

<h1>Login</h1>
<form action="" method="post">
<table align="left" border="0" cellspacing="0" cellpadding="3">
<tr><td>Username:</td><td><input type="text" name="user" maxlength="30"></td></tr>
<tr><td>Password:</td><td><input type="password" name="pass" maxlength="30"></td></tr>
<tr><td colspan="2" align="left"><input type="checkbox" name="remember">
<font size="2">Remember me next time</td></tr>
<tr><td colspan="2" align="right">
    <input name="Join" type="button" value="Join"><input type="submit" name="sublogin" value="Login"></td></tr>
<tr><td colspan="2" align="left">&nbsp;</td></tr>
</table>
</form>

<?
  }
}


/**
 * Checks to see if the user has submitted his
 * username and password through the login form,
 * if so, checks authenticity in database and
 * creates session.
 */
if(isset($_POST['sublogin'])){
  /* Check that all fields were typed in */
  if(!$_POST['user'] || !$_POST['pass']){
      die('You didn\'t fill in a required field.');
  }
  /* Spruce up username, check length */
  $_POST['user'] = trim($_POST['user']);
  if(strlen($_POST['user']) > 30){
      die("Sorry, the username is longer than 30 characters, please shorten it.");
  }

  /* Checks that username is in database and password is correct */
  $md5pass = md5($_POST['pass']);
  $result = confirmUser($_POST['user'], $md5pass);

  /* Check error codes */
  if($result == 1){
      die('That username doesn\'t exist in our database.');
  }
  else if($result == 2){
      die('Incorrect password, please try again.');
  }

  /* Username and password correct, register session variables */
  $_POST['user'] = stripslashes($_POST['user']);
  $_SESSION['username'] = $_POST['user'];
  $_SESSION['password'] = $md5pass;

  /**
    * This is the cool part: the user has requested that we remember that
    * he's logged in, so we set two cookies. One to hold his username,
    * and one to hold his md5 encrypted password. We set them both to
    * expire in 100 days. Now, next time he comes to our site, we will
    * log him in automatically.
    */
  if(isset($_POST['remember'])){
      setcookie("cookname", $_SESSION['username'], time()+60*60*24*100, "/");
      setcookie("cookpass", $_SESSION['password'], time()+60*60*24*100, "/");
  }

  /* Quick self-redirect to avoid resending data on refresh */
  echo "<meta http-equiv=\"Refresh\" content=\"0;url=$HTTP_SERVER_VARS[PHP_SELF]\">";
  return;
}

/* Sets the value of the logged_in variable, which can be used in your code */
$logged_in = checkLogin();

?>

<<?
session_start();
include("database.php");

/**
 * Returns true if the username has been taken
 * by another user, false otherwise.
 */
function usernameTaken($username){
  global $conn;
  if(!get_magic_quotes_gpc()){
      $username = addslashes($username);
  }
  $q = "select username from users where username = '$username'";
  $result = mysql_query($q,$conn);
  return (mysql_numrows($result) > 0);
}

/**
 * Inserts the given (username, password) pair
 * into the database. Returns true on success,
 * false otherwise.
 */
function addNewUser($username, $password){
  global $conn;
  $q = "INSERT INTO users VALUES ('$username', '$password')";
  return mysql_query($q,$conn);
}

/**
 * Displays the appropriate message to the user
 * after the registration attempt. It displays a
 * success or failure status depending on a
 * session variable set during registration.
 */
function displayStatus(){
  $uname = $_SESSION['reguname'];
  if($_SESSION['regresult']){
?>

<h1>Registered!</h1>
<p>Thank you <b><? echo $uname; ?></b>, your information has been added to the database, you may now <META HTTP-EQUIV="Refresh"
      CONTENT="2; URL=/login.php"><a href="main.php" title="Login">log in</a>.</p>

<?
  }
  else{
?>

<h1>Registration Failed</h1>
<p>We're sorry, but an error has occurred and your registration for the username <b><? echo $uname; ?></b>, could not be completed.<br>
Please try again at a later time.</p>

<?
  }
  unset($_SESSION['reguname']);
  unset($_SESSION['registered']);
  unset($_SESSION['regresult']);
}

if(isset($_SESSION['registered'])){
/**
 * This is the page that will be displayed after the
 * registration has been attempted.
 */
?>

<html>
<title>Registration Page</title>
<body>

<? displayStatus(); ?>

</body>
</html>

<?
  return;
}

/**
 * Determines whether or not to show to sign-up form
 * based on whether the form has been submitted, if it
 * has, check the database for consistency and create
 * the new account.
 */
if(isset($_POST['subjoin'])){
  /* Make sure all fields were entered */
  if(!$_POST['user'] || !$_POST['pass']){
      die('You didn\'t fill in a required fields.<br>
      You shall now be re-directed to the registration form.
      <META HTTP-EQUIV="Refresh"
      CONTENT="2; URL=http://www.sabregames.com/register.php">.');
  }

  /* Spruce up username, check length */
  $_POST['user'] = trim($_POST['user']);
  if(strlen($_POST['user']) > 30){
      die("Sorry, the username is longer than 30 characters, please shorten it.");
  }

  /* Check if username is already in use */
  if(usernameTaken($_POST['user'])){
      $use = $_POST['user'];
      die("Arg! someone beat you to it, the username: <strong>$use</strong> is already taken, I guess you have to choose another.");
  }

  /* Add the new account to the database */
  $md5pass = md5($_POST['pass']);
  $_SESSION['reguname'] = $_POST['user'];
  $_SESSION['regresult'] = addNewUser($_POST['user'], $md5pass);
  $_SESSION['registered'] = true;
  echo "<meta http-equiv=\"Refresh\" content=\"0;url=$HTTP_SERVER_VARS[PHP_SELF]\">";
  return;
}
else{
/**
 * This is the page with the sign-up form, the names
 * of the input fields are important and should not
 * be changed.
 */
?>

<html>
<title>Registration Page</title>
<body>
<h1>Register</h1>
<form action="<? echo $HTTP_SERVER_VARS['PHP_SELF']; ?>" method="post">
<table align="left" border="0" cellspacing="0" cellpadding="3">
<tr><td>Username:</td><td><input type="text" name="user" maxlength="30"></td></tr>
<tr><td>Password:</td><td><input type="password" name="pass" maxlength="30"></td></tr>
<tr><td colspan="2" align="right"><input type="submit" name="subjoin" value="Join!"></td></tr>
</table>
</form>
</body>
</html>


<?
}
?>

<?
/* Include Files *********************/
session_start();
include("database.php");
include("login.php");
/*************************************/
?>

<html>
<title>Jasons Login Script</title>
<body>

<? displayLogin(); ?>

</body>
</html>

<?
/* Include Files *********************/
session_start();
include("database.php");
include("login.php");
/*************************************/
?>

<html>
<title>Jasons Login Script</title>
<body>

<?
if($logged_in){
  echo 'Logged in as '.$_SESSION['username'].', <a href="logout.php">logout</a>';
}else{
  echo 'Not logged in.';
}
?>

</body>
</html>