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Gabriel's Interest Rate Calculator

CODE FOLLOWS

<?php



include('../includes/header.php');



// code

error_reporting(E_ALL);    // set error reporting to all



echo('<h1>Gabriel\'s Interest Rate Calculator</h1>');



// Note the variables being passed via the POST ternary operators.



$step = isset($_POST['step']) ? $_POST['step'] : 0;

$principal = isset($_POST['principal']) ? $_POST['principal'] : '';

$interest = isset($_POST['interest']) ? $_POST['interest'] : '';

$term = isset($_POST['term']) ? $_POST['term'] : '';



// filter all input taken from the Browser

$step = htmlentities($step);

$principal = htmlentities($principal);

$interest = htmlentities($interest);

$term = htmlentities($term);



if ($step == 0)    // first time into this form

{

    ?>



    <form action="interestrate.php" method="POST">

        <label for="name">Principal</label>

        <input type="text" size="36" id="name" name="principal" value="">

        <br><br>

        <label for="name">Interest Rate as Decimal Number</label>

        <input type="text" size="36" id="name" name="interest" value="">

        <br><br>

        <label for="name">Loan Term in Years</label>

        <input type="text" size="36" id="name" name="term" value="">

        <br><br>

        <input type="hidden" name="step" value="1">

        <input type="submit" name="submit" value="Submit">

    </form>



    <?php

} else  // else show what the form gathered

{



    echo('<p>The following is what the form gathered</p>');

    echo('<p>Please note: The POST array has not been scrubbed</p>');

    echo('<p>Thus, it is open to javascript insertion.</p>');

    echo('<pre>');

    print_r($_POST);    // note this dumps the entire contents of the $_POST array

    echo('</pre>');



    $total = $interest * $principal * $term + $principal;

    $interesttotal = $total - $principal;

    $payment = round(($total / ($term * 12)),2);



    echo("<h3>Total Repayment = $total</h3>");

    echo("<h3>Total Interest Paid = $interesttotal</h3>");

    echo("<h3>Monthly Payment = $payment</h3>");



    // provide a form to try again

    ?>



    <form action="interestrate.php" method="POST">

        <input type="hidden" name="step" value="0">

        <input type="submit" name="submit" value="Try Again">

    </form>



    <?php

}



include('../includes/footer.php');

?>
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