简单的 PHP 计算器答案

【问题标题】：Simple PHP calculator简单的 PHP 计算器
【发布时间】：2014-02-22 02:12:37
【问题描述】：

我正在创建一个基本的 PHP 计算器，它允许您输入两个值并选择您的运算符，然后显示答案。一切正常，只是没有向浏览器输出答案。

以下是我的 html 和 PHP 文件的代码：

<head>
<meta charset="utf-8">
<title>Calculator</title>
</head>
<body>
<form method="post" attribute="post" action="disp_form.php">
<p>First Value:<br/>
<input type="text" id="first" name="first"></p>
<p>Second Value:<br/>
<input type="text" id="second" name="second"></p>
<input type="radio" name="group1" id="add" value="add" checked="true"><p>+</p><br/>
<input type="radio" name="group1" id="subtract" value="subtract"><p>-</p><br/>
<input type="radio" name="group1" id="times" value="times"><p>x</p><br/>
<input type="radio" name="group1" id="divide" value="divide"><p>/</p><br/>
<p></p>
<button type="submit" name="answer" id="answer" value="answer">Calculate</button>
</form>
</body>
</html>

PHP 文件：

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Answer</title>
</head>
<body>
<p>The answer is: 
<?php
if($_POST['group1'] == add) {
echo "$first + $second";
}
else if($_POST['group1'] == subtract) {
echo "$first - $second";
}
else if($_POST['group1'] == times) {
echo "$first * $second";
}
else($_POST['group1'] == divide) {
echo "$first / $second";
}
?>
</p> 
</body>
</html>

【问题讨论】：

标签： php calculator

【解决方案1】：

你需要分配 $first 和 $second

$first = $_POST['first'];
$second= $_POST['second'];

另外，正如 Travesty3 所说，您需要在引号之外进行算术运算：

echo $first + $second;

【讨论】：

您还需要在引号之外进行计算。否则，您将只输出两个数字，并在它们之间使用运算符，而不是实际进行计算。并将add、subtract 等放在引号中。

【解决方案2】：

您需要以相同的方式获取值以获取计算器操作，如下所示：

<?php
if($_POST['group1'] == add) {
echo "$_POST['first']+ $_POST['second'];
}
... and so on
?>

或者，为了更容易，只需这样做：

    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Answer</title>
</head>
<body>
<p>The answer is: 
<?php
$first = $_POST['first'];
$second= $_POST['second'];

if($_POST['group1'] == add) {
echo "$first + $second";
}
else if($_POST['group1'] == subtract) {
echo "$first - $second";
}
else if($_POST['group1'] == times) {
echo "$first * $second";
}
else($_POST['group1'] == divide) {
echo "$first / $second";
}
?>
</p> 
</body>
</html>

【讨论】：

【解决方案3】：

$first = doubleval($_POST['first']);
$second = doubleval($_POST['second']);

if($_POST['group1'] == 'add') {
    echo "$first + $second = ".($first + $second);
}

// etc

【讨论】：

【解决方案4】：

我个人会做一个切换而不是所有这些 if, else if, else

$first = $_POST['first'] + 0;//a small "hack" to make sure its an int but allow negs!!
$second= $_POST['second'] + 0;
$operator = $_POST["group1"];
switch($operator)
{
    case "add"
    echo "Answer is: " .$first + $second;
    break; 
    case "subtract"
    echo "Answer is: " .$first - $second;
    break;
    case "times"
    echo "Answer is: " .$first * $second;
    break; 
    case "divide"
    echo "Answer is: " .$first / $second;
    break;
}

【讨论】：

【解决方案5】：

您还需要将 [== 'add'] 数学运算放在引号中

if($_POST['group1'] == 'add') {
echo $first + $second;
}

完整的代码应该是这样的：

<?php
$first = $_POST['first'];
$second= $_POST['second'];
if($_POST['group1'] == 'add') {
echo $first + $second;
}
else if($_POST['group1'] == 'subtract') {
echo $first - $second;
}
else if($_POST['group1'] == 'times') {
echo $first * $second;
} 
else if($_POST['group1'] == 'divide') {
echo $first / $second;
}
?>

【讨论】：

【解决方案6】：

使用单引号检查字符串

例如。 $_POST['group1'] == 'add'

【讨论】：

【解决方案7】：

<?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="                =                "></td>
    </tr>

</table>
</form>

【讨论】：

【解决方案8】：

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Calculator</title>
    </head>
    <body>
    HTML Code is here:

         <form method="post">
            <input type="text" name="numb1">
            <input type="text" name="numb2">
            <select name="operator" id="">
               <option>None</option>
               <option>Add</option>
               <option>Subtract</option>
               <option>Multiply</option>
               <option>Divide</option>
               <option>Square</option>
            </select>
            <button type="submit" name="submit" value="submit">Calculate</button>
         </form>

    PHP Code:

        <?php 

            if (isset($_POST['submit'])) {
                $result1 = $_POST['numb1'];
                $result2 = $_POST['numb2'];
                $operator = $_POST['operator'];
                switch ($operator) {
                    case 'None':
                        echo "You need to select any operator";
                        break;
                    case 'Add':
                        echo $result1 + $result2;
                        break;
                    case 'Subtract':
                        echo $result1 - $result2;
                        break;
                    case 'Multiply':
                        echo $result1 * $result2;
                        break;
                    case 'Divide':
                        echo $result1 / $result2;
                        break;
                    case 'Square':
                        echo $result1 ** $result2;
                        break;
                }
            }


         ?>
        enter code here

    </body>
    </html>

【讨论】：

虽然此代码 sn-p 可能是解决方案，但包含解释确实有助于提高帖子的质量。请记住，您是在为将来的读者回答问题，而这些人可能不知道您提出代码建议的原因
感谢您提供此代码 sn-p，它可能会提供一些有限的即时帮助。 proper explanation would greatly improve its long-term value 通过展示为什么这是一个很好的解决问题的方法，并将使其对未来有其他类似问题的读者更有用。请edit您的回答添加一些解释，包括您所做的假设。

【解决方案9】：

在 php 文件中进行此更改

<html>
<head>
<meta charset="utf-8">
<title>Answer</title>
</head>
<body>
<p>The answer is: 
<?php
$first = $_POST['first'];
$second= $_POST['second'];
if($_POST['group1'] == 'add') {
echo $first + $second;
}
else if($_POST['group1'] == 'subtract') {
echo $first - $second;
}
else if($_POST['group1'] == 'times') {
echo $first * $second;
}

else if($_POST['group1'] == 'divide') {
echo $first / $second;
}
else {
    echo "Enter the numbers properly";
}
?>
</p> 
</body>
</html>

【讨论】：

你好！欢迎来到stackoverflow。您可能想解释一下您的代码，以及您添加了哪些更改。
为 if 语句添加 else 部分。操作 id(add,subtract,...) 必须在引号 ('') 中指定。并且必须计算并打印答案，因此，应删除 echo 后的引号（''），因为 ('') 将打印语句而不是答案。

【解决方案10】：

<?php
$cal1= $_GET['cal1'];
$cal2= $_GET['cal2'];
$symbol =$_GET['symbol'];


if($symbol == '+')
{
    $add = $cal1 + $cal2;
    echo "Addition is:".$add;
}

else if($symbol == '-')
{
    $subs = $cal1 - $cal2;
    echo "Substraction is:".$subs;
}

 else if($symbol == '*')
{
    $mul = $cal1 * $cal2;
    echo "Multiply is:".$mul;
}

else if($symbol == '/')
{
    $div = $cal1 / $cal2;
    echo "Division is:".$div;
}

  else
{

    echo "Oops ,something wrong in your code son";
}


?>

【讨论】：

这不是一个好的答案。看这里->stackoverflow.com/help/how-to-answer

【解决方案11】：

<!DOCTYPE html>
<html lang="en" dir="ltr">
    <head>
        <meta charset="utf-8">
        <title>Calculator</title> 
    </head>
<body>

    <form method="GET">
    <h1>Calculator</h1>
    <p>This is a calculator made by Hau Teen Yee Fabrice and is free to use.</p>
        <ul>
     <ol> Multiplication: * </ol>
     <ol> Substraction: - </ol>
     <ol> Division: / </ol>
     <ol> Addition: + </ol>
        </ul>
     <p>Enter first number:</p>
        <input type="text" name="cal1">
        <p>Enter second number:</p>
        <input type="text" name="cal2">
        <p>Enter the calculator symbol</p>
        <input type="text" name="symbol">
        <button>Calculate</button>
    </form>
    <?php
    $cal1= $_GET['cal1'];
    $cal2= $_GET['cal2'];
    $symbol =$_GET['symbol'];

    if($symbol == '+')
    {
        $add = $cal1 + $cal2;
        echo "Addition is:".$add;
    }
    else if($symbol == '-')
    {
        $subs = $cal1 - $cal2;
        echo "Substraction is:".$subs;
    }
     else if($symbol == '*')
    {
        $mul = $cal1 * $cal2;
        echo "Multiply is:".$mul;
    }
    else if($symbol == '/')
    {
        $div = $cal1 / $cal2;
        echo "Division is:".$div;
    }
      else
    { 
        echo "Oops ,something wrong in your code son";
    }
    ?>
    </body> 
</html>

【讨论】：