public function currency($currency = null) {
        $currency = $currency == null ? $this->currency : $currency;
        return $this->getWord($this->number) . ' ' . $currency;
    }
public function currency($currency = null) {
        $currency = $currency == null ? $this->currency : $currency;
        return $this->getWord($this->number) . ' ' . $currency;
    }
public function currency ( $ currency = null ) { $ currency = $ currency == null ? $ this -> currency : $ currency ; return $ this -> getWord ( $ this -> number ) . ' ' . $ currency ; }
return currency string of number

@param string $currency
@return string
return currency string of number