新手求大神指点

lh4111 2013-02-01 12:05:47

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">

<head>

<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

<title>无标题文档</title>





</head>

<center>

<body>

<?php 

	$numa = true;

	$numb = true;

	$a = true;

	$b = true;

	

	if (isset($_GET["sub"])){

		$message = "";

		if ($_GET["num1"]==""){                         //若注释这一段判断代码 $sum 可以输出

			$numa = false;

			$message .= "第一个数不能为空</br>";

		}

		

		if (!is_numeric($_GET["num1"])){

			$a = false;

			$message .= "第一个数必须为数字</br>";

		}

		

		if ($_GET["num2"]==""){

			$numb = false;

			$message .= "第二个数不能为空</br>";

		}

		

		if (!is_numeric($_GET["num2"])){

			$b = false;

			$message .= "第二个数必须为数字</br>";

			

			if ($a && $b && $numa && $numb){

				$sum = 0;

				switch ($_GET["ysf"]){

					case "+" : $sum = $_GET["num1"] + $_GET["num2"];break;

					case "-" : $sum = $_GET["num1"] - $_GET["num2"];break;

					case "x" : $sum = $_GET["num1"] * $_GET["num2"];break;

					case "/" : $sum = $_GET["num1"] / $_GET["num2"];break;

					case "%" : $sum = $_GET["num1"] % $_GET["num2"];break;

					}



			}

		}

	}

?>

<table width="500" border="0">

<caption><h1>计算器</h1></caption>

<form id="form1" name="form1" method="get" action="">

    <tr>

    <td width="118" align="center">

      <input name="num1" type="text" id="num1" value="<?php echo $_GET["num1"]; ?>" size="9" maxlength="9" />

    </td>

    <td width="76" align="center"><select name="ysf" id="ysf">

      <option value="+" <?php if($_GET["ysf"]=="+") echo "selected" ?>>+</option>

      <option value="-" <?php if($_GET["ysf"]=="-") echo "selected" ?>>-</option>

      <option value="x" <?php if($_GET["ysf"]=="x") echo "selected" ?>>x</option>

      <option value="/" <?php if($_GET["ysf"]=="/") echo "selected" ?>>/</option>

      <option value="%" <?php if($_GET["ysf"]=="%") echo "selected" ?>>%</option>

    </select></td>

    <td width="149" align="center"><input name="num2" type="text" id="num2" size="9" maxlength="9" value="<?php echo$_GET["num2"]; ?>"/></td>

    <td width="139" align="center"><input type="submit" name="sub" id="sub" value="计算" /></td>

  </tr>

  <?php

  if (isset($_GET["sub"])){

  		echo "<tr><td colspan = 4 >";

			if ($a && $b && $numa && $numb){

					echo "结果： {$_GET['num1']} {$_GET['ysf']} {$_GET['num2']} = {$sum}";   

				}else {

					echo $message;

				}

		echo "</td></tr>";

  }

  

  ?>

 </form>

</table>



</body>

</center>

</html>

...全文

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xuzuning 2013-02-01

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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gbk" />
<title>无标题文档</title>
 
 
</head>
<center>
<body>
<?php
if(! isset($_GET['sub'])) $_GET = array( 'num1' => '', 'num2' => '', 'ysf' => '+');

$numa = true;
$numb = true;
$a = true;
$b = true;
$sum = '';
     
if (isset($_GET["sub"])){
  $message = "";
  if ($_GET["num1"]==""){
    $numa = false;
    $message .= "第一个数不能为空</br>";
  }
  if (!is_numeric($_GET["num1"])){
    $a = false;
    $message .= "第一个数必须为数字</br>";
  }
  if ($_GET["num2"]==""){
    $numb = false;
    $message .= "第二个数不能为空</br>";
  }
  if (!is_numeric($_GET["num2"])){
    $b = false;
    $message .= "第二个数必须为数字</br>";
  }
  if ($a && $b && $numa && $numb){
    switch ($_GET["ysf"]){
      case "+" : $sum = $_GET["num1"] + $_GET["num2"];break;
      case "-" : $sum = $_GET["num1"] - $_GET["num2"];break;
      case "x" : $sum = $_GET["num1"] * $_GET["num2"];break;
      case "/" : $sum = $_GET["num1"] / $_GET["num2"];break;
      case "%" : $sum = $_GET["num1"] % $_GET["num2"];break;
    }
  }
}
?>
<table width="500" border="0">
<caption><h1>计算器</h1></caption>
<form id="form1" name="form1" method="get" action="">
    <tr>
    <td width="118" align="center">
      <input name="num1" type="text" id="num1" value="<?php echo $_GET["num1"]; ?>" size="9" maxlength="9" />
    </td>
    <td width="76" align="center"><select name="ysf" id="ysf">
      <option value="+" <?php if($_GET["ysf"]=="+") echo "selected" ?>>+</option>
      <option value="-" <?php if($_GET["ysf"]=="-") echo "selected" ?>>-</option>
      <option value="x" <?php if($_GET["ysf"]=="x") echo "selected" ?>>x</option>
      <option value="/" <?php if($_GET["ysf"]=="/") echo "selected" ?>>/</option>
      <option value="%" <?php if($_GET["ysf"]=="%") echo "selected" ?>>%</option>
    </select></td>
    <td width="149" align="center"><input name="num2" type="text" id="num2" size="9" maxlength="9" value="<?php echo$_GET["num2"]; ?>"/></td>
    <td width="139" align="center"><input type="submit" name="sub" id="sub" value="计算" /></td>
  </tr>
  <?php
  if (isset($_GET["sub"])){
          echo "<tr><td colspan = 4 >";
            if ($a && $b && $numa && $numb){
                    echo "结果： {$_GET['num1']} {$_GET['ysf']} {$_GET['num2']} = {$sum}";  //$sum 无法输出。 
                }else {
                    echo $message;
                }
        echo "</td></tr>";
  }
   
  ?>
 </form>
</table>
 
</body>
</center>
</html>

lh4111 2013-02-01

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这是注释

if ($_GET["num1"]==""){                       

$numa = false;

$message .= "第一个数不能为空</br>";

}



if (!is_numeric($_GET["num1"])){

$a = false;

$message .= "第一个数必须为数字</br>";

}



if ($_GET["num2"]==""){

$numb = false;

$message .= "第二个数不能为空</br>";

}



if (!is_numeric($_GET["num2"])){

$b = false;

$message .= "第二个数必须为数字</br>";