}

class

 Cattle 

extends

 Animal{

public

 

function

 speak(){

//在这里可以添加一些 Cattle 逻辑

return

 "Cattle speak<br />";

}
}

$oDog

=

new

 Dog();

echo

(

$oDog

->run());

echo

(

$oDog

->speak());

$oCattle

=

new

 Cattle();

echo

(

$oCattle

->run());

echo

(

$oCattle

->speak());

?>