Question

我是php的新手我正在尝试打印错误消息如果一个人在该字段中插入任何其他内容而不是实数。我希望这里的代码是有意义的，请描述你是如何解决它的，谢谢：

<?php
$result = "";
 class calculator
{
var $a;
var $b;

function checkopration($oprator)
{
    switch($oprator)
    {
        case '+':
        return $this->a + $this->b;
        break;

        case '-':
        return $this->a - $this->b;
        break;

        case '*':
        return $this->a * $this->b;
        break;

        case '/':
        return $this->a / $this->b;
        break;

        default:
        return "Sorry No command found";
    }
}
function getresult($a, $b, $c)
{
    $this->a = $a;
    $this->b = $b;
    return $this->checkopration($c);
}
}

$cal = new calculator();
if(isset($_POST['submit']))
{
     $result = $cal->getresult($_POST['n1'],$_POST['n2'],$_POST['op']);
}
?>

  <form method="post">
  <table align="center">
     <tr>
       <td><strong><?php echo $result; ?><strong></td>
   </tr>
   <tr>
          <td>Enter 1st Number</td>
    <td><input type="text" name="n1"></td>
</tr>

<tr>
    <td>Enter 2nd Number</td>
    <td><input type="text" name="n2"></td>
</tr>

<tr>
    <td>Select Oprator</td>
    <td><select name="op">
        <option value="+">+</option>
        <option value="-">-</option>
        <option value="*">*</option>
        <option value="/">/</option>
    </select></td>
</tr>

<tr>
    <td></td>
    <td><input type="submit" name="submit" value="Submit"></td>
</tr>

 </table>
 </form>

Answer 1

<?php
$result = "";
 class calculator
 {
   var $a;
   var $b;

   function checkopration($oprator)
   {
       switch($oprator)
       {
         case '+':
           return $this->a + $this->b;
           break;

         case '-':
           return $this->a - $this->b;
           break;

         case '*':
           return $this->a * $this->b;
           break;

         case '/':
           return $this->a / $this->b;
           break;

         default:
           return "Sorry No command found";
       }
   }
   function getresult($a, $b, $c)
   {
       $this->a = $a;
       $this->b = $b;
       return $this->checkopration($c);
   }
 }

$cal = new calculator();
if(isset($_POST['submit']))
{
  $n1=$_POST['n1'];
  $n2=$_POST['n2'];
  $op=$_POST['op'];
  if(is_numeric($n1)&&is_numeric($n2)){
       $result = $cal->getresult($n1,$n2,$op);
  }else{
    $result="<p style='background-color:#FFCCCC'><b>ERROR: </b>Invalid input</p><br>";
  }
}
?>

  <form method="post">
  <table align="center">
     <tr>
       <td><strong><?php echo $result; ?><strong></td>
   </tr>
   <tr>
          <td>Enter 1st Number</td>
    <td><input type="text" name="n1"></td>
</tr>

<tr>
    <td>Enter 2nd Number</td>
    <td><input type="text" name="n2"></td>
</tr>

<tr>
    <td>Select Oprator</td>
    <td><select name="op">
        <option value="+">+</option>
        <option value="-">-</option>
        <option value="*">*</option>
        <option value="/">/</option>
    </select></td>
</tr>

<tr>
    <td></td>
    <td><input type="submit" name="submit" value="Submit"></td>
</tr>

 </table>
 </form>

Answer 2

您正在寻找的是is_numeric()功能看看：http://php.net/manual/de/function.is-numeric.php

Answer 3

使用php中的is_numberic（）函数，您可以检查输入的值是否为数字，如果不是，我们可以返回错误消息

<?php
$result = "";
 class calculator
{
var $a;
var $b;

function checkopration($oprator)
{
    switch($oprator)
    {
        case '+':
        return $this->a + $this->b;
        break;

        case '-':
        return $this->a - $this->b;
        break;

        case '*':
        return $this->a * $this->b;
        break;

        case '/':
        return $this->a / $this->b;
        break;

        default:
        return "Sorry No command found";
    }
}
function getresult($a, $b, $c)
{
    $this->a = $a;
    $this->b = $b;
    return $this->checkopration($c);
}
}

$cal = new calculator();
if(isset($_POST['submit']))
{
    if(is_numeric($_POST['n1']) && is_numeric($_POST['n2'])){
        $result = $cal->getresult($_POST['n1'],$_POST['n2'],$_POST['op']);
    }else{
        $result="please only insert numbers into the calculator";
    }
}
?>

无效输入上的Php错误消息

3 个答案: