php - sum of 2 number with object and method -

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• php: “notice: undefined variable”, “notice: undefined index”, , “notice: undefined offset” 23 answers

why getting these errors? undefined variable: num1 cannot access empty property

class sum{     public $num1=1; public function fun($num2){      return $this->$num1+$num2;     } } $number = new sum(); echo $number->fun(3); 

class sum{    public $num1=1;    public function fun($num2){         return $this->num1+$num2;           //removed $^^    } } $number = new sum(); echo $number->fun(3);