写出下列程序的输出结果
<?php class a { protected $c; public function a() { $this->c = 10; } } class b extends a { public function print_data() { return $this->c; } } $b = new b(); echo $b->print_data(); ?>
<?php class a{ protected $c; public function a(){ $this->c = 10; echo "in a constructor...<br/>"; } } class b extends a{ public function print_data(){ echo "in b print_data...<br/>"; return $this->c; } } $x = new b(); echo $x->print_data(); //10 echo $x->c; // error: can't access protected property b::$c ?>