PHP can't extend from interface?

Question

I write below in a single php file.

<?php
interface people
{
    public function take($s);
}

class engineer extends people
{
    public function take($s){
        echo $s;
    }
}
?>

The people is an interface, the engineer extends people. But when I run this code, the error:

Fatal error: Class engineer cannot extend from interface people in E:\php5\Mywwwroot\b.php on line 12

What's happened? My PHP version is 5.4.

Answer 1

You implement interfaces and extend classes:

<?php
interface people
{
    public function take($s);
}

class engineer implements people
{
    public function take($s){
        echo $s;
    }
}
?>

Answer 2

extends is for extending another class.

For interfaces, you need to use implements instead.

(An interface can extend another interface, though)

Answer 3

Depends on what you want, it could be:

• class extends aClass
• class implements anInterface
• interface extends anInterface

You can extend only one class/interface and implement many interfaces. You can extend interface to another interface, e.g. interface DieselEngineInterface extends EngineInterface.

Also want to note a comment, now that you can have class and interface hierarchy, you need to know when to use them.