任务：
创建file1.php, file2.php, file3.php 分别定义不同的命名空间 分别定义⽅法：foo()，定义类Demo，定义常量NUMBER 创建main.php，并在其中引⼊file123，并分别调⽤其中的⽅法，创建类并输出常量。
file1.php
<?php
namespace task1\File1;
function foo()
{
echo "file1.php\n";
}
?>
file2.php
<?php
namespace task1\File2;
class Demo{
private $name;
public function __construct(){
$this->name = "class defined in task1\\file2\\Demo";
}
public function speak(string $na){
echo $na. " is an object from ".$this->name . "\n";
}
}
?>
file3.php
<?php
namespace task1\File3;
const NUMBER = 266;
?>
main.php
<?php
require("./file1.php");
require("./file2.php");
require("./file3.php");
use function task1\File1\foo as foo1;
foo1();
echo "</br>\n";
$demo1=new task1\File2\Demo();
$demo1->speak("demo1");
echo "</br>\n";
use const task1\File3\NUMBER as number1;
echo number1."\n";
echo "</br>\n";
?>
运行结果
task1运行结果.jpg
