这是我得到的错误:-
致命错误:无法使用'Parent‘作为类名,因为它是在第3行的C:\xampp\htdocs\test\home.php中保留的
下面是我的代码:
<?php
class Parent{
public $num1 = 3;
}
class Child extends Parent{
public $sum = 2 + $this->num1;
}
$obj = new Child();
echo $obj->sum;
?>
发布于 2018-06-25 00:22:42
不能使用Parent
作为类名,可以使用$sum = 2 + $this->num1;
为$sum
赋一个初始值。
// renamed parent class
class ParentClass {
public $num1 = 3;
}
// renamed child class
class ChildClass extends ParentClass {
public $sum ;
// a constructor is where you would do this type of math
function __construct() {
$this->sum = 2 + $this->num1;
}
}
// create your child object
$obj = new ChildClass();
echo $obj->sum;
发布于 2018-06-25 00:59:06
您定义变量的方式错误,变量应为var $num = 3;
class Parent{
var $num1 = 3;
}
class Child extends Parent{
public function sum() {
return 2 + $this->num1;
}
}
$obj = new Child();
echo $obj->sum();
https://stackoverflow.com/questions/51011629
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