<!DOCTYPE html>
<html lang="sk">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>PHP Kalkulačka</title>
<style>
body {
font-family: Arial, sans-serif;
margin: 40px;
text-align: center;
}
form {
display: inline-flex;
align-items: center;
gap: 10px;
}
input, select, button {
padding: 8px;
font-size: 18px;
}
.result {
margin-top: 20px;
font-size: 22px;
font-weight: bold;
}
</style>
</head>
<body>
<h1>Kalkulačka v PHP</h1>
<form method="post">
<input type="number" step="any" name="cislo1" required
value="<?php echo isset($_POST['cislo1']) ? $_POST['cislo1'] : ''; ?>">
<select name="operacia">
<option value="+" <?php if(isset($_POST['operacia']) && $_POST['operacia'] == '+'
echo 'selected'; ?>>+</option>
<option value="-" <?php if(isset($_POST['operacia']) && $_POST['operacia'] == '-' echo 'selected'; ?>>-</option>
<option value="*" <?php if(isset($_POST['operacia']) && $_POST['operacia'] == '*' echo 'selected'; ?>>×</option>
<option value="/" <?php if(isset($_POST['operacia']) && $_POST['operacia'] == '/' echo 'selected'; ?>>÷</option>
</select>
<input type="number" step="any" name="cislo2" required
value="<?php echo isset($_POST['cislo2']) ? $_POST['cislo2'] : ''; ?>">
<button type="submit">=</button>
</form>
<div class="result">
<?php
if ($_SERVER["REQUEST_METHOD"] == "POST" {
$cislo1 = $_POST['cislo1'];
$cislo2 = $_POST['cislo2'];
$operacia = $_POST['operacia'];
$vysledok = "";
switch ($operacia) {
case '+':
$vysledok = $cislo1 + $cislo2;
break;
case '-':
$vysledok = $cislo1 - $cislo2;
break;
case '*':
$vysledok = $cislo1 * $cislo2;
break;
case '/':
if ($cislo2 != 0) {
$vysledok = $cislo1 / $cislo2;
} else {
$vysledok = "Nedá sa deliť nulou!";
}
break;
}
echo "Výsledok: " . $vysledok;
}
?>
</div>
</body>
</html>