if (!is_numeric($this->num2)) {
die("<script>alert('第二个数不为数字！');history.go(-1);</script>");
}
}
function operate()
{
switch ($this->op) {
case '+':
$result = $this->num1 + $this->num2;
break;
case '-':
$result = $this->num1 - $this->num2;
break;
case '*':
$result = $this->num1 * $this->num2;
break;
case '/':
if ($this->num2 == 0) {
die("<script>alert('被除数不能为0！！');history.go(-1);</script>");
}
$result = $this->num1 / $this->num2;
break;
default:
}
$this->res = $result;
}
}
$answer = new Calculator($_POST['num1'], $_POST['op'], $_POST['num2']);
$answer->operate();
$resu = $answer->res;
echo '答案是：' . $resu;
