h2
<?php
$result = '';
$operator = '';
$firstNumber = '';
$secondNumber = '';
if ($_SERVER["REQUEST_METHOD"] == "POST") {
$firstNumber = $_POST['firstNumber'];
$secondNumber = $_POST['secondNumber'];
$operator = $_POST['operator'];
switch ($operator) {
case 'add':
$result = $firstNumber + $secondNumber;
break;
case 'subtract':
$result = $firstNumber - $secondNumber;
break;
case 'multiply':
$result = $firstNumber * $secondNumber;
break;
case 'divide':
if ($secondNumber != 0) {
$result = $firstNumber / $secondNumber;
} else {
$result = "Error: Division by zero!";
}
break;
default:
$result = "Invalid operator";
}
}
?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>PHP Calculator</title>
</head>
<body>
<h1>Simple PHP Calculator</h1>
<form method="POST" action="">
<input type="number" name="firstNumber" value="<?= $firstNumber ?>" required>
<select name="operator" required>
<option value="add" <?= $operator == 'add' ? 'selected' : '' ?>>+</option>
<option value="subtract" <?= $operator == 'subtract' ? 'selected' : '' ?>>-</option>
<option value="multiply" <?= $operator == 'multiply' ? 'selected' : '' ?>>*</option>
<option value="divide" <?= $operator == 'divide' ? 'selected' : '' ?>>/</option>
</select>
<input type="number" name="secondNumber" value="<?= $secondNumber ?>" required>
<button type="submit">Calculate</button>
</form>
<?php if ($result !== ''): ?>
<h2>Result: <?= $result ?></h2>
<?php endif; ?>
</body>
</html>