How do I go about creating wordpress users programmatically?

**I am using the method below, user is being created - but when I try to login with a password it gives me wrong password message, any suggestions please?**

```
include 'wp-blog-header.php';
include 'wp-includes/registration.php';
include 'wp-includes/pluggable.php';
ini_set("memory_limit","1024M");
ini_set("max_execution_time", "240");
global $wpdb;
programmatically
$row = array(
    'user_name' => "wacek123",
    'password' => "wacek123",
    'email_address' => "wacek123@gmail.com",
    'name' => "wacek123",
    'surname' => "wacek123"
    );

$userdata = array(
    'user_login' => $row["user_name"],
    'user_pass' => wp_hash_password($row["password"]),
    'user_nicename' => $row["user_name"],
    'user_email' => $row["email_address"],
    'first_name'  => $row["name"],
    'last_name'  => $row["surname"],
    'role' => 'subscriber'
    );
wp_insert_user($userdata);

```