Untitled


<html>
<head>
    <meta charset="UTF-8">
</head>
<body>
<?php
if (isset($_GET['N1'])){
    $a = ($_GET['N1']);
    }
if (isset($_GET['N2'])) {
    $b = ($_GET['N2']);
    }
?>
<form >
    Number 1: <input type="text" name="N1" value="<?php
    if (isset($_GET['N1'])){
        echo ($_GET['N1']);
    } ?>" > <br>
    Number 2: <input type="text" name="N2" value="<?php if (isset($_GET['N2'])) {
        echo ($_GET['N2']);
    } ?>"> <br>
    <hr>
    <input type="radio" name="Operation" value="+"> + <br>
    <input type="radio" name="Operation" value="-"> - <br>
    <input type="radio" name="Operation" value="*"> * <br>
    <input type="radio" name="Operation" value="/"> / <br>
    <hr>
    <br> <input type="submit"  name="submit" value="="> <br>
    <?php
    switch( $_GET['Operation'] ) {
        case '+':
            echo $a + $b ;
            break;
        case '-' :
            echo $a - $b ;
            break;
        case '*':
            echo $a * $b ;
            break;
        case '/' :
            if ($b == 0) {
                echo 'error';
            }
            else {
                echo $a / $b ;
            }
            break;
    }
    ?>
</form>
</body>
</html>