为什么这个简单的hello world PHP代码不起作用？

Question

class saySomething {

    var $helloWorld = 'hello world';

    function sayHelloWorld($helloWorld)
    {
        echo $helloWorld;
    }

}

$saySomething = new saySomething();
$saySomething->sayHelloWorld();

the above gives this error:

Warning: Missing argument 1 for saySomething::sayHelloWorld(), called in C:\xampp\htdocs\test.php on line 15 and defined in C:\xampp\htdocs\test.php on line 7

Answer 1

Because you're missing argument 1 for saySomething::sayHelloWorld(). When you defined the function, you defined it as having 1 required argument.

Define your function like this:

class saySomething {

    var $helloWorld = 'hello world';

    function sayHelloWorld()
    {
        echo $this->helloWorld;
    }

}