baeclass
    public function get_all_uids(){
      $b = array();
      $sql = "SELECT COUNT(*) FROM users";
      if($r = $this->con->query($sql)){
        if($r->fetchColumn() > 0){
          $sql = "SELECT id FROM users";
          foreach($this->con->query($sql) as $u){
            $b[] = $u['id'];
          }
        }
      }
      return $b;
    }

acp.php
elseif($_GET["sub"] == "allaccs"){
  $ids = $base->get_all_uids();
?>
    <div>
      <div class="landing-section" id="features">
        <div class="container">
          <div class="row gutter30 landing-features">
            <div class="col-sm-10">
              <h3 class="features-title"><?php print_r($ids);?></h3>
              <p class="features-text"><br>
<?php
  echo "<table width=\"80%\" border=\"2\">
  <tr>
  <th>id</th>
  <th>Username</th>
  <th>Email </th>
  <th>InviteCode</th>
  </tr>";

  foreach($ids as $id){
    $user = new user($id);
    $user->init();
    echo "<tr>";
    echo "<td>" . $id . "</td>";
    echo "<td>" . $user->get_name() . "</td>";
    echo "<td>" . $user->get_email() . "</td>";
    echo "<td>add codes</td>";
    echo "</tr>";
  }

  echo "</table>";
?>
            </div>
          </div>
        </div>
      </div>
    </div>
<?php
}