Problem connecting to database

I’m new to PHP programming and at the start I have a problem.
I learning from book "Build your own database driven web site using PHP&MYSQL.
I have problem with example 4.
When connecting to a MySQL database throws me an error. When connecting to the following

<?php
$link = mysqli_connect('localhost', 'root', 'password');
if (!$link)
{
    $output = 'Unable to connect to the database server.';
    include 'output.html.php';
    exit();
}

if (!mysqli_set_charset($link, 'utf8'))
{
    $output = 'Unable to set database connection encoding.';
    include 'output.html.php';
    exit();
}

if (!mysqli_select_db($link, 'ijdb'))
{
    $output = 'Unable to locate the joke database.';
    include 'output.html.php';
    exit();
}

$output = 'Database connection established.';
include 'output.html.php';
?>
I have error
Warning: mysqli_connect(): (HY000/1045): Access denied for user 'root'@'localhost' (using password: YES) in C:\\xampp\\htdocs\\owndatabase\\connect\\index.php on line 2

in output.html.php code is:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
        "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
    <head>
        <title>PHP Output</title>
        <meta http-equiv="content-type"
                content="text/html; charset=utf-8"/>
    </head>
    <body>
        <p>
            <?php echo $output; ?>
        </p>
    </body>
</html>

I change XAMPP MySQL root password through SQL update:
UPDATE mysql.user SET Password=PASSWORD(‘password’) WHERE User=‘root’; FLUSH PRIVILEGES;
and in C://xampp/ phpmyadmin / config.inc.php i change cfg[‘Servers’][$i][‘password’] = ‘mypassword’;

When I use code without password

<?php
$link = mysqli_connect('localhost', 'root' );
if (!$link)
{
    $output = 'Unable to connect to the database server.';
    include 'output.html.php';
    exit();
}

if (!mysqli_set_charset($link, 'utf8'))
{
    $output = 'Unable to set database connection encoding.';
    include 'output.html.php';
    exit();
}

if (!mysqli_select_db($link, 'ijdb'))
{
    $output = 'Unable to locate the joke database.';
    include 'output.html.php';
    exit();
}

$output = 'Database connection established.';
include 'output.html.php';
?>

I don’t have error.

UPDATE mysql.user SET Password=PASSWORD(‘password’) WHERE User=‘root’@‘localhost’;

Then flush.

http://dev.mysql.com/doc/refman/5.0/en/set-password.html

Still nothing, I have error

And are you sure you did flush privileges after changing the password?

Yes I’m sure, I reinstalled twice XAMMP and nothing. I try to use WampServer and MYSQL