php - while loop does not increment -

there weird problem while loop not incrementing displaying first category not rest this:

class temp  { var $file;  function new_list($forum_list) {     foreach($forum_list $key => $value)     {         $this->file = str_replace('{'.$key.'}', $value, $this->file);     }     return $this->file; }  function display() {     echo $this->file; } }   $temp = new temp();  // mysql query  while ($row_cat = mysql_fetch_array($cat)){     $temp->new_list(array(         'cat_title' => $row_cat['title'],         'cat_description' => $row_cat['description']     ));      $cid = $row_cat['id'];      // mysql query      while ($row_forum = mysql_fetch_array($forum)){         $temp->new_list(array(             'forum_title' => $row_forum['title'],             'forum_description' => $row_forum['description']         ));     } } $temp->display(); 

now have made template engine , uses array usual displays category description , subcategory , description once first entry why have made wrong?

edit: have added template engine code catches file , use file_get_contents method , converts keys values , when use without engine works fine engine shows first column.

try simplify find error. dont see problem youve posted suspect theres error in logic of code havent posted. try this:

<-- mysql query -->  while ($row_cat = mysql_fetch_array($cat)){ echo $row_cat['title']."<br/>";  $cid = $row_cat['id'];  <-- mysql query -->  while ($row_forum = mysql_fetch_array($forum)){ "-".$row_forum['title']."<br/>"; } } 

update:

yup: heres problem: $this->file = ... overwriting $file each iteration. need concat result (add strings . ) this:

$this->file = $this->file . str_replace('{'.$key.'}', $value, $this->file);