<?php
include("../includes/header.php");
error_reporting(E_ALL);
date_default_timezone_set("America/Detroit");
echo("<h1>Ernest's Smart Calculator — Decisions and Loops Demo</h1>");
if ($_SERVER["REQUEST_METHOD"] != "POST") {
?>
<form method="POST" action="smart_calculator.php">
<p>Enter first number: <input type="number" step="any" name="num1" required></p>
<p>Enter second number: <input type="number" step="any" name="num2" required></p>
<p>
Select operation:
<select name="operation" required>
<option value="">-- Choose --</option>
<option value="add">Add</option>
<option value="subtract">Subtract</option>
<option value="multiply">Multiply</option>
<option value="divide">Divide</option>
</select>
</p>
<input type="submit" value="Calculate">
</form>
<?php
} else {
echo("<h2>Calculation Result</h2>");
$num1 = isset($_POST['num1']) ? floatval($_POST['num1']) : 0;
$num2 = isset($_POST['num2']) ? floatval($_POST['num2']) : 0;
$operation = isset($_POST['operation']) ? $_POST['operation'] : "";
switch ($operation) {
case "add":
$result = $num1 + $num2;
echo("<p>$num1 + $num2 = <b>$result</b></p>");
break;
case "subtract":
$result = $num1 - $num2;
echo("<p>$num1 - $num2 = <b>$result</b></p>");
break;
case "multiply":
$result = $num1 * $num2;
echo("<p>$num1 × $num2 = <b>$result</b></p>");
break;
case "divide":
if ($num2 != 0) {
$result = $num1 / $num2;
echo("<p>$num1 ÷ $num2 = <b>$result</b></p>");
} else {
echo("<p style='color:red;'><b>Error:</b> Division by zero is not allowed.</p>");
}
break;
default:
echo("<p>Please select a valid operation.</p>");
}
echo("<h3>Multiplication Table for $num1</h3>");
for ($i = 1; $i <= 10; $i++) {
echo("$num1 × $i = " . ($num1 * $i) . "<br>");
}
echo("<p><a href='smart_calculator.php'>Try Again</a></p>");
}
include("../includes/footer.php");
?>