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php实现计算器

2026-02-13 17:46:58PHP

基础实现

使用PHP创建一个简单的计算器需要处理用户输入、执行运算并返回结果。以下是一个基于表单提交的示例：

<?php
$result = '';
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $num1 = $_POST['num1'];
    $num2 = $_POST['num2'];
    $operator = $_POST['operator'];

    switch ($operator) {
        case '+':
            $result = $num1 + $num2;
            break;
        case '-':
            $result = $num1 - $num2;
            break;
        case '*':
            $result = $num1 * $num2;
            break;
        case '/':
            $result = ($num2 != 0) ? $num1 / $num2 : "除数不能为零";
            break;
    }
}
?>
<form method="post">
    <input type="number" name="num1" required>
    <select name="operator">
        <option value="+">+</option>
        <option value="-">-</option>
        <option value="*">*</option>
        <option value="/">/</option>
    </select>
    <input type="number" name="num2" required>
    <button type="submit">计算</button>
</form>
<?php if ($result !== ''): ?>
    <p>结果: <?php echo $result; ?></p>
<?php endif; ?>

安全增强

添加输入验证和过滤防止非法输入：

$num1 = filter_input(INPUT_POST, 'num1', FILTER_VALIDATE_FLOAT);
$num2 = filter_input(INPUT_POST, 'num2', FILTER_VALIDATE_FLOAT);
if ($num1 === false || $num2 === false) {
    $result = "请输入有效数字";
}

扩展功能

支持更多运算符和连续计算：

case '^':
    $result = pow($num1, $num2);
    break;
case '%':
    $result = $num1 % $num2;
    break;

前端优化

使用HTML5增强用户体验：

<input type="number" step="any" name="num1" placeholder="第一个数字">
<input type="number" step="any" name="num2" placeholder="第二个数字">

完整示例

结合所有改进的完整代码：

<?php
$result = '';
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $num1 = filter_input(INPUT_POST, 'num1', FILTER_VALIDATE_FLOAT);
    $num2 = filter_input(INPUT_POST, 'num2', FILTER_VALIDATE_FLOAT);
    $operator = $_POST['operator'];

    if ($num1 === false || $num2 === false) {
        $result = "无效输入";
    } else {
        switch ($operator) {
            case '+': $result = $num1 + $num2; break;
            case '-': $result = $num1 - $num2; break;
            case '*': $result = $num1 * $num2; break;
            case '/': $result = ($num2 != 0) ? $num1 / $num2 : "除数不能为零"; break;
            case '^': $result = pow($num1, $num2); break;
            case '%': $result = $num1 % $num2; break;
            default: $result = "未知运算符";
        }
    }
}
?>
<!DOCTYPE html>
<form method="post">
    <input type="number" step="any" name="num1" required>
    <select name="operator">
        <option value="+">+</option>
        <option value="-">-</option>
        <option value="*">×</option>
        <option value="/">÷</option>
        <option value="^">^</option>
        <option value="%">%</option>
    </select>
    <input type="number" step="any" name="num2" required>
    <button type="submit">=</button>
</form>
<?php if ($result !== ''): ?>
    <output>结果: <?php echo htmlspecialchars($result); ?></output>
<?php endif; ?>

php实现计算器