Create a user programmatically in Drupal

<?php
/**
 * Creates a new user.
 * 
 * @param string $name Required user name.
 * @param array $roles Optional array of roles.
 * @param string $mail Optional email address.
 * @param string $password Optional custom password.
 * @return type
 */
function temppp_add_user($name, $roles = array(), $mail = '', $password = '') {
 
  if (empty($password)) {
    $password = $name;
  }
  if (empty($roles)) {
    $roles = array(
      DRUPAL_AUTHENTICATED_RID => 'authenticated user',
    );
  }
  if (empty($mail)) {
    $mail = "$name@$name.com";
  }
  $fields = array(
    'name' => $name,
    'mail' => $mail,
    'pass' => $password,
    'status' => 1,
    'init' => 'email address',
    'roles' => $roles,
  );
 
  // Leaves the first parameter blank so a new user is created.
  return user_save('', $fields);
}