PHP’de Sayıları Yazıya Nasıl Çeviririz?

<!DOCTYPE>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Numarayı Yazıya Çevirme</title>
</head>

<body>
<form method="post" action="">
  <label>Sayı Giriniz
  <input type="text" name="textfield" onchange="convert_number_to_words()" />
  </label>
  <input type="submit" value="Çevir" />
</form>
<p>
  Equivalent  in words: 
  <?php
function convert_number_to_words($number) {
   
    $hyphen      = '-';
    $conjunction = '  ';
    $separator   = ' ';
    $negative    = 'eksi ';
    $decimal     = ' nokta ';
    $dictionary  = array(
        0                   => 'Sıfır',
        1                   => 'Bir',
        2                   => 'İki',
        3                   => 'Üç',
        4                   => 'Dört',
        5                   => 'Beş',
        6                   => 'Altı',
        7                   => 'Yedi',
        8                   => 'Sekiz',
        9                   => 'Dokuz',
        10                  => 'On',
        11                  => 'OnBir',
        12                  => 'Onİki',
        13                  => 'OnÜç',
        14                  => 'OnDört',
        15                  => 'OnBeş',
        16                  => 'OnAltı',
        17                  => 'OnYedi',
        18                  => 'OnSekiz',
        19                  => 'OnDokuz',
        20                  => 'Yirmi',
        30                  => 'Otuz',
        40                  => 'Kırk',
        50                  => 'Elli',
        60                  => 'Atmış',
        70                  => 'Yetmiş',
        80                  => 'Seksen',
        90                  => 'Doksan',
        100                 => 'Yüz',
        1000                => 'Bin',
        1000000             => 'Milyon',
        1000000000          => 'Milyar',
        1000000000000       => 'Trilyon',
        1000000000000000    => 'Katrilyon',
        1000000000000000000 => 'Kentrilyon'
    );
   
    if (!is_numeric($number)) {
        return false;
    }
   
    if (($number >= 0 && (int) $number < 0) || (int) $number < 0 - PHP_INT_MAX) {
        // overflow
        trigger_error(
            'convert_number_to_words only accepts numbers between -' . PHP_INT_MAX . ' and ' . PHP_INT_MAX,
            E_USER_WARNING
        );
        return false;
    }

    if ($number < 0) {
        return $negative . convert_number_to_words(abs($number));
    }
   
    $string = $fraction = null;
   
    if (strpos($number, '.') !== false) {
        list($number, $fraction) = explode('.', $number);
    }
   
    switch (true) {
        case $number < 21:
            $string = $dictionary[$number];
            break;
        case $number < 100:
            $tens   = ((int) ($number / 10)) * 10;
            $units  = $number % 10;
            $string = $dictionary[$tens];
            if ($units) {
                $string .= $hyphen . $dictionary[$units];
            }
            break;
        case $number < 1000:
            $hundreds  = $number / 100;
            $remainder = $number % 100;
            $string = $dictionary[$hundreds] . ' ' . $dictionary[100];
            if ($remainder) {
                $string .= $conjunction . convert_number_to_words($remainder);
            }
            break;
        default:
            $baseUnit = pow(1000, floor(log($number, 1000)));
            $numBaseUnits = (int) ($number / $baseUnit);
            $remainder = $number % $baseUnit;
            $string = convert_number_to_words($numBaseUnits) . ' ' . $dictionary[$baseUnit];
            if ($remainder) {
                $string .= $remainder < 100 ? $conjunction : $separator;
                $string .= convert_number_to_words($remainder);
            }
            break;
    }
   
    if (null !== $fraction && is_numeric($fraction)) {
        $string .= $decimal;
        $words = array();
        foreach (str_split((string) $fraction) as $number) {
            $words[] = $dictionary[$number];
        }
        $string .= implode(' ', $words);
    }
   
    return $string;
}

echo '<b>'.convert_number_to_words($_POST['textfield']).'</b>';
?>
</p>
</body>
</html>