一个表单问题

错误太多。改成这样：===============jisu1.php==================
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>计算器</title>
</head>
<?php
$calculator_ids = array("+","-","*","/");switch($_POST['jishu']){
   case "+": $result=$_POST['num1']+$_POST['num2']; break;
   case "-": $result=$_POST['num1']-$_POST['num2']; break;
   case "*": $result=$_POST['num1']*$_POST['num2']; break;
   case "/": $result=$_POST['num1']/$_POST['num2']; break;
}
?>
<body>
<form action="jisu1.php" method="post">
第一个数：<input name="num1" type="text" size="10" maxlength="10">
第二个数：<input name="num2" type="text" size="10" maxlength="10"><br><font face="Arial, Helvetica, sans-serif"></font>
<input name="jishu" type="radio" value="<?php echo $calculator_ids[0] ?>" checked>+<br>
<input name="jishu" type="radio" value="<?php echo $calculator_ids[1] ?>" >-<br>
<input name="jishu" type="radio" value="<?php echo $calculator_ids[2] ?>" >*<br>
<input name="jishu" type="radio" value="<?php echo $calculator_ids[3] ?>" >/<br>
结果是<?php echo $result?><br>
<input name="" type="submit" value="计算">
<input name="" type="reset" value="重新">
</form>
</body>
</html>
==============jisu1.php END================