<?php

//Structura Database
//DB: users
//user_id INT(24) NOT NULL AUTO_INCREMENT
//username VARCHAR(12) NOT NULL
//password VARCHAR(10) NOT NULL

if(isset($_POST['submit'])){

$errors = array();

    if(isset($_POST['username']))
    {
        if(strlen($_POST['username']) < 2)
        {
            $errors[] = 'The username cannot be longer than 30 characters.<br /><a href="register.php">Back</a><br />';
        }
        if(strlen($_POST['username']) > 10)
        {
            $errors[] = 'The username cannot be longer than 10 characters.<br /><a href="register.php">Back</a><br />';
        }

    }
    else
    {
        $errors[] = 'The username field must not be empty.';
    }


    if(isset($_POST['password']))
    {
        if($_POST['password'] != $_POST['checkpassword'])
        {
            $errors[] = 'The two passwords did not match.<br /><a href="register.php">Back</a><br />';
        }
    }
    else
    {
        $errors[] = 'The password field cannot be empty.<br /><a href="register.php">Back</a><br />';
    }

 if(!empty($errors))
    {
        foreach($errors as $key => $value)
        {
            echo  $value;
        }
    }
    else
    {

    $dbuser = $_POST['username'];

    $tabela_utilizator = $dbuser.'_table';
    $table = "CREATE TABLE $tabela_utilizator IF NOT EXISTS(
    user_id INT(24) NOT NULL AUTO_INCREMENT,
    username VARCHAR(12) NOT NULL,
    password VARCHAR(10) NOT NULL
    )";

    $sqlq = mysql_query($table);
    if(!$sqlq){
    print 'Table can&prime;t be created';
    }else{
    $sql = "INSERT INTO $tabela_utilizator(username, password) VALUES('" . mysql_real_escape_string($_POST['username']) . "','" . md5($_POST['password']) . "')";
    $insert = mysql_query($sql);
    print 'Utilizator inregistrat cu succes.';
    }

  }


}else{

print '
<form action="" method="POST">
<input type="text" name="username" size="21">
<input type="password" name="password" size="21">
<input type="password" name="checkpassword" size="21">
<input type="submit" name="submit" value="Inregistreaza cont">
</form>
';

}
?>


Sign in(logare)

<?php

if(isset($_SESSION['logat']) && $_SESSION['logat'] == true)
{
    echo 'Esti deja logat,te poti  <a href="signout.php">deloga</a> daca vrei.';


}
else
{

if($_SERVER['REQUEST_METHOD'] != 'POST')
    {
        /*the form hasn't been posted yet, display it
          note that the action="" will cause the form to post to the same page it is on */
        echo '<form method="post" action="">
                <input type="text" name="username" size="21">
                <input type="password" name="password" size="21">
                <input type="submit" name="submit" value="Inregistreaza cont">
        <input type="submit" value="Sign in" />
         </form>';
    }
    else
    {
        $errors = array();

        if(empty($_POST['username']))
        {
            $errors[] = 'Campul userului este gol.';
        }

        if(empty($_POST['password']))
        {
            $errors[] = 'Campul parola este gol.';
        }

        if(!empty($errors))
        {
            echo 'Cateva probleme la logare<br /><br />';
            echo '<ul>';
            foreach($errors as $key => $value)
            {
                echo '<li>' . $value . '</li>';
            }
            echo '</ul>';
        }
        else
        {
            //the form has been posted without errors, so save it
            //notice the use of mysql_real_escape_string, keep everything safe!
            //also notice the sha1 function which hashes the password
            $sql = "SELECT
                        user_id,
                        username,
                        password
                    FROM
                        users
                    WHERE
                        username = '" . mysql_real_escape_string($_POST['username']) . "'
                    AND
                        password = '" . md5($_POST['password']) . "'";

            $result = mysql_query($sql);
            if(!$result)
            {

                echo 'ERROR.';
                /
            }
            else
                if(mysql_num_rows($result) == 0)
                {
                    echo 'Ai incercat gresit o combinatie de user si parola.Incearca mai tarziu.';
                }
                else
                {
                    $_SESSION['logat'] = true;

                    while($row = mysql_fetch_assoc($result))
                    {
                        $_SESSION['user_id']    = $row['user_id'];
                        $_SESSION['username']   = $row['username'];
                    }

                       echo 'Bine ai venit, ' . $_SESSION['username'] . '. <br /><a href="index.php">Dute la pagina index.</a>.';
                }
            }
        }
    }

 }
?>