php命名空间

index.php:<?phpinclude 'demo.php';use A\demo as test;use B\demo as test2;use C\demo;$obj = new test();$obj = new test2();echo B\b."";class c extends demo{}$obj = new c();$obj -> say();demo.php:<?phpnamespace A;class demo{public function __construct(){echo __NAMESPACE__."";}}namespace B;const b = 'I am in namespace B';class demo{public function __construct() {echo __NAMESPACE__."";}}namespace C;class demo{public function say(){echo 'Class C say...';}}