<?php

$nwords = array(    "khong", "mot", "hai", "ba", "bon", "nam", "sau", "bay",
                     "tam", "chin", "Muoi", "Muoi mot", "Muoi hai", "Muoi ba",
                     "Muoi bon", "Muoi lam", "Muoi sau", "Muoi bay", "Muoi tam",
                     "Muoi chin", "Hai muoi", 30 => "Ba muoi", 40 => "BOn muoi",
                     50 => "Nam muoi", 60 => "Sau moi", 70 => "Bay muoi", 80 => "Tam muoi",
                     90 => "Chin muoi" );

function int_to_words($x)
{
     global $nwords;
     if(!is_numeric($x))
     {
         $w = '#';
     }else if(fmod($x, 1) != 0)
     {
         $w = '#';
     }else{
         if($x < 0)
         {
             $w = 'minus ';
             $x = -$x;
         }else{
             $w = '';
         }
         if($x < 21)
         {
             $w .= $nwords[$x];
         }else if($x < 100)
         {
             $w .= $nwords[10 * floor($x/10)];
             $r = fmod($x, 10);
             if($r > 0)
             {
                 $w .= '-'. $nwords[$r];
             }
         } else if($x < 1000)
         {
             $w .= $nwords[floor($x/100)] .' <b>Tram</b>';
             $r = fmod($x, 100);
             if($r > 0)
             {
                 $w .= ' and '. int_to_words($r);
             }
         } else if($x < 1000000)
         {
             $w .= int_to_words(floor($x/1000)) .' <b>Ngan</b>';
             $r = fmod($x, 1000);
             if($r > 0)
             {
                 $w .= ' ';
                 if($r < 100)
                 {
                     $w .= 'and ';
                 }
                 $w .= int_to_words($r);
             }
         } else {
             $w .= int_to_words(floor($x/1000000)) .' <b>Trieu</b>';
             $r = fmod($x, 1000000);
             if($r > 0)
             {
                 $w .= ' ';
                 if($r < 100)
                 {
                     $word .= 'and ';
                 }
                 $w .= int_to_words($r);
             }
         }
     }
     return $w;
}

// demonstration

if(isset($_POST['num']))
{
     echo '
     the number reads <b>'.$_POST['num'].'</b>:<br />'.int_to_words($_POST['num']).'<p>
     <a href="'.$_SERVER['PHP_SELF'].'">try again</a>';
}else{
     echo '
     <form method="post" action="'.$_SERVER['PHP_SELF'].'">
         <input type="text" name="num">
         <input type="submit" value="spell number">
     </form>';
}

?>