在变量声明上为变量赋值

Question

我试图将变量声明如下：

class GumballMachine {

private static $SOLD_OUT = 0;
private $state = $SOLD_OUT;
    private function GumballMachine (){}
}

如何将$ SOLD_OUT的值分配给$ state或者还有其他方法吗？

Answer 1

您可以使用class constants

执行此操作

    const SOLD_OUT = 0;
    private $state = self::SOLD_OUT;

Answer 2

您需要使用常量值。此外，您需要将构造函数声明为public，否则您将遇到错误。

class GumballMachine {
    const SOLD_OUT = 0;

    private $state = self::SOLD_OUT;

    public function GumballMachine () { }
}

Answer 3

`class GumballMachine {

 private static $SOLD_OUT = 0;
 private $state = 0;
private function GumballMachine ()
 {
  $this->state=$SOLD_OUT;
 }
}`