PHP pa和ma

 <?php

 class Mouse
 {
     private $color;
     public $sex;

     public function __construct($role){
         switch($role){
             case 'pa':
                 $this->color = 'black';
                 $this->sex = 'male';
                 break;
             case 'ma':
                 $this->color = 'white';
                 $this->sex = 'female';
                 break;
             default:
                 throw new Exception('pa Or ma,please!');
         }
     }

     public function getColor(Mouse $mouse){
         if($mouse->sex == $this->sex){
             var_dump($this->color);
         }else{
             var_dump('*****');
         }
     }

     public function mateWithMa(Mouse $ma){
         if($this->sex == 'male' && $ma->sex = 'female'){
             var_dump('You have been trust by ma');
             $ma->color = $this->color;
             var_dump("success to mate! ma's color :" .($ma->color));
         }
     }

     public function mateWithPa(Mouse $pa){
         if($this->sex == 'female' && $pa->sex == 'male'){
             var_dump('You have been trust by pa');
             $pa->color = $this->color;
             var_dump("success to mate! pa's color :" .($pa->color));
         }
     }
 }

 var_dump('The First Couple :');
 $pa1 = new Mouse('pa');
 $ma1 = new Mouse('ma');
 $pa1->mateWithMa($ma1);
 $ma1->mateWithPa($pa1);

 echo "\n";

 var_dump('The Second Couple :');
 $pa2 = new Mouse('pa');
 $ma2 = new Mouse('ma');
 $ma2->mateWithPa($pa2);
 $pa2->mateWithMa($ma2);

此文相关php知识点见 ：http://www.php-internals.com/book/?p=chapt05/05-03-class-visibility