php基本计算器带有函数和开关，但结果是

以下是完整的代码：

<?php
$num1 = $_POST['num1'];
$num2 = $_POST['num2'];
$calcu = $_POST['calcu'];
    function calculate($n1,$n2, $calcu) // set $calcu as parameter
    {
        switch($calcu)
        {
        case "Addition": // here you have to use colons not semi-colons
            $compute = $n1 + $n2; 
            break;
        case "Subtraction":
            $compute = $n1 - $n2; 
            break;
        case "Multiplication":
            $compute = $n1 * $n2; 
            break;
        case "Division":
            $compute = $n1 / $n2; 
            break;
        }
        return $compute; // returning variable
    }
echo "$calcu <br /> <br /> 1st Number: $num1 <br /> 2nd Number: $num2 <br /><br />";
echo "Answer is:" .calculate($num1,$num2, $calcu); // you need to pass $calcu as argument of that function
?>

将switch('$calcu')更改为switch($calcu)。应该是这样。

但不仅如此。您的变量是未定义的，因为您试图在提交表单之前对它们进行寻址，即它们还不存在。

$num1 = $_POST['num1'];
$num2 = $_POST['num2'];
$calcu = $_POST['calcu'];

你在那里称呼他们

echo "$calcu <br /> <br /> 1st Number: $num1 <br /> 2nd Number: $num2 <br /><br />";
echo "Answer is:" .calculate($num1,$num2);

实现这一点的正确方法是检查是否提交了表格：

    <input type="radio" value= "Addition" name="calcu"> Addition .<br />
    <input type="radio" value= "Subtraction" name="calcu"> Subtraction .<br />
    <input type="radio" value= "Multiplication" name="calcu"> Multiplication .<br />
    <input type="radio" value= "Division" name="calcu"> Division .<br />
<?php
if (isset($_POST)){
    $num1 = $_POST['num1'];
    $num2 = $_POST['num2'];
    $calcu = $_POST['calcu'];
        function calculate($n1,$n2)
        {
            switch('$calcu')
            {
            case "Addition";
                $compute = $n1 + $n2; 
                break;
            case "Subtraction";
                $compute = $n1 - $n2; 
                break;
            case "Multiplication";
                $compute = $n1 * $n2; 
                break;
            case "Division";
                $compute = $n1 / $n2; 
                break;
            }
        }
    echo "$calcu <br /> <br /> 1st Number: $num1 <br /> 2nd Number: $num2 <br /><br />";
    echo "Answer is:" .calculate($num1,$num2);
    unset($_POST);
}
?>

将switch('$calcu')更改为switch($calcu)。

正如@PeterM所提到的，您正在访问超出范围的变量$calcu。要么将$calcu变量传递给fun calculate，要么通过$_POST数组直接访问。

使用CCD_ 9。

或

function calculate($n1,$n2, $calcu) {
...
}

用calculate($n1,$n2, $calcu)称之为乐趣。