Recional

<?
    error_reporting(1);

    class RationalChislo {
        public $a = 0;
        public $b = 0;

        public function __construct ($a, $b){
            if(is_numeric($a)) {
                $this->a = $a;
            }
            if(is_numeric($b) && ($b != 0)) {
                $this->b = $b;
            }
        }
    }
    class RationalCalculator {
        public function add($x, $y) {
            if(is_a($x, 'RationalChislo') && is_a($y, 'RationalChislo')){
                $Temp = new RationalChislo();
                if( $x->b == $y->b )
                {
                    $Temp->a = $x->a + $y->a;
                    $Temp->b = $x->b;
                }
                else
                {
                    $Temp->b = $x->b * $y->b;
                    $Temp->a = ($Temp->b / $x->b * $x->a ) + ($Temp->b / $y->b * $y->a );
                }
                $t1 = $Temp->a;
                $t2 = $Temp->b;
                $nod = Nod($t1, $t2);
                $Temp->a = $Temp->a / $nod;
                $Temp->b = $Temp->b / $nod;
                return $Temp;
            }
            else return null;
        }
        public function sub($x, $y) {
            if(is_a($x, 'RationalChislo') && is_a($y, 'RationalChislo')) {
                $Temp = new RationalChislo();
                if( $x->b == $y->b )
                {
                    $Temp->a = $x->a - $y->a;
                    $Temp->b = $x->b;
                }
                else
                {
                    $Temp->b = $x->b * $y->b;
                    $Temp->a = ($Temp->b / $x->b * $x->a ) - ($Temp->b / $y->b * $y->a );
                }
                return $Temp;
            }
            else return null;
        }

        public function mult($x, $y) {
            if(is_a($x, 'RationalChislo') && is_a($y, 'RationalChislo')){
                $Temp = new RationalChislo();
                $Temp->a = $x->a * $y->a;
                $Temp->b = $x->b * $y->b;
                return $Temp;
            }
            else return null;
        }

        public function div($x, $y) {
            if(is_a($x, 'RationalChislo') && is_a($y, 'RationalChislo')){
                $Temp = new RationalChislo();
                $Temp->a = $x->a * $y->b;
                $Temp->b = $x->b * $y->a;
                return $Temp;
            }
            else return null;
        }

        public function Nod($x, $y) {
            while ($x != $y) {
                if ($x > $y) $x =  $x - $y;
                else $y = $y - $x;
            }
            return $y;
        }

        /*public function reduce($q){
            $nod = NOD($q->a,$->$b);
            $q->a = $q->a/$nod;
            $q->b = $q->b/$nod;
            return $q;
        }*/
    }
?>