<?php 
namespace foo;
function test1(){
    echo "namespace....";
}
?>

<?php
include '1.php';
use foo as a;
a\test1();
?>

<?php
namespace app\fruit;
class apple{
    function eat(){
        echo "eat....";
    }
    
    function play(){
        echo "play....";
    }
}

function test(){
    echo "test...";
}
?>

<?php
/*
 * 必须把1.php文件包含进来
 * 否则出错：Fatal error: Call to undefined function app\fruit\test() in
 *                     D:\wamp\www\test\2.php on line 9
 */
include '1.php';
use app\fruit as a;//用use来取别名
a\test();    //调用1.php里的一个方法
$a = new a\apple();    //实例化1.php里的一个对象
$a->eat();
?>