switch ($op) { case '+': $this->result = $array_num[0] + $array_num[1]; echo "result = " . $this->result . "</br>"; break; case '/': if ($array_num[1] == 0) { die("除数不能为0!") . "</br>"; } else { $this->result = (double) $array_num[0] / $array_num[1]; echo "result = " . $this->result . "</br>"; } break; case '*': $this->result = $array_num[0] * $array_num[1]; echo "result = " . $this->result . "</br>"; break; case '-': $this->result = $array_num[0] - $array_num[1]; echo "result = " . $this->result . "</br>"; break; default: die("未知错误"); break; } } } $str_get = $_POST['num']; $calculator1 = new calculator("{$str_get}"); $calculator1->option($calculator1->op);