PHP基于工厂模式实现的计算器实例

abstract class Calculator{ private $number1; private $number2; public $result; /**  * @return the $number2  */ public function getNumber2() {  return $this->number2; } /**  * @param field_type $number2  */ public function setNumber2($number2) {  $this->number2 = $number2; } /**  * @return the $number1  */ public function getNumber1() {  return $this->number1; } /**  * @param field_type $number1  */ public function setNumber1($number1) {  $this->number1 = $number1; } abstract function get_result(); }class Add extends Calculator{  public function get_result($number1,$number2)  {   return $number1+$number2;  }}class Sub extends Calculator{  public function get_result($number1,$number2)  {   return $number1-$number2;  }}class Mul extends Calculator{  public function get_result($number1,$number2)  {   return $number1*$number2;  }}class Div extends Calculator{  public function get_result($number1,$number2)  {   return $number1/$number2;  }}class Factory{  public function Building($notes)  {   if($notes=="+")   {    $add=new Add();    return $add;   }   elseif ($notes=="-")   {    $sub=new Sub();    return $sub;   }   elseif($notes=="*")   {    $mul=new Mul();    return $mul;   }   else   {    $div=new Div();    return $div;   }  }}