Question: display the results below the form instead of on a seperate page and after each calculation, set the values in the text boxes to empty strings display_results.php - 30 ) { $error_message = 'Years must be less than 31.'; // set error message to empty string if no invalid entries } else { $error_message = ''; } // if an error message exists, go to the index page if ($error_message != '') { include('index.php'); exit(); } // calculate the future value $future_value = $investment; for ($i = 1; $i <= $years; $i++) { $future_value = $future_value + ($future_value * $interest_rate * .01); } // apply currency and percent formatting $investment_f = '$'.number_format($investment, 2); $yearly_rate_f = $interest_rate.'%'; $future_value_f = '$'.number_format($future_value, 2); ?> Future Value Calculator Future Value Calculator Investment Amount: Yearly Interest Rate: Number of Years: Future Value: index.php Future Value Calculator Future Value Calculator Investment Amount: Yearly Interest Rate: Number of Years:
Question: display the results below the form instead of on a seperate page and after each calculation, set the values in the text boxes to empty strings
display_results.php -
<?php
// get the data from the form
$investment = filter_input(INPUT_POST, 'investment',
FILTER_VALIDATE_FLOAT);
$interest_rate = filter_input(INPUT_POST, 'interest_rate',
FILTER_VALIDATE_FLOAT);
$years = filter_input(INPUT_POST, 'years',
FILTER_VALIDATE_INT);
// validate investment
if ($investment === FALSE ) {
$error_message = 'Investment must be a valid number.';
} else if ( $investment <= 0 ) {
$error_message = 'Investment must be greater than zero.';
// validate interest rate
} else if ( $interest_rate === FALSE ) {
$error_message = 'Interest rate must be a valid number.';
} else if ( $interest_rate <= 0 ) {
$error_message = 'Interest rate must be greater than zero.';
// validate years
} else if ( $years === FALSE ) {
$error_message = 'Years must be a valid whole number.';
} else if ( $years <= 0 ) {
$error_message = 'Years must be greater than zero.';
} else if ( $years > 30 ) {
$error_message = 'Years must be less than 31.';
// set error message to empty string if no invalid entries
} else {
$error_message = '';
}
// if an error message exists, go to the index page
if ($error_message != '') {
include('index.php');
exit(); }
// calculate the future value
$future_value = $investment;
for ($i = 1; $i <= $years; $i++) {
$future_value =
$future_value + ($future_value * $interest_rate * .01);
}
// apply currency and percent formatting
$investment_f = '$'.number_format($investment, 2);
$yearly_rate_f = $interest_rate.'%';
$future_value_f = '$'.number_format($future_value, 2);
?>
<!DOCTYPE html>
<html>
<head>
<title>Future Value Calculator</title>
<link rel="stylesheet" type="text/css" href="main.css">
</head>
<body>
<main>
<h1>Future Value Calculator</h1>
<label>Investment Amount:</label>
<span><?php echo $investment_f; ?></span><br>
<label>Yearly Interest Rate:</label>
<span><?php echo $yearly_rate_f; ?></span><br>
<label>Number of Years:</label>
<span><?php echo $years; ?></span><br>
<label>Future Value:</label>
<span><?php echo $future_value_f; ?></span><br>
</main>
</body>
</html>
index.php
<?php
//set default value of variables for initial page load
if (!isset($investment)) { $investment = ''; }
if (!isset($interest_rate)) { $interest_rate = ''; }
if (!isset($years)) { $years = ''; }
?>
<!DOCTYPE html>
<html>
<head>
<title>Future Value Calculator</title>
<link rel="stylesheet" type="text/css" href="main.css">
</head>
<body>
<main>
<h1>Future Value Calculator</h1>
<?php if (!empty($error_message)) { ?>
<p class="error"><?php echo htmlspecialchars($error_message); ?></p>
<?php } ?>
<form action="display_results.php" method="post">
<div id="data">
<label>Investment Amount:</label>
<input type="text" name="investment"
value="<?php echo htmlspecialchars($investment); ?>">
<br>
<label>Yearly Interest Rate:</label>
<input type="text" name="interest_rate"
value="<?php echo htmlspecialchars($interest_rate); ?>">
<br>
<label>Number of Years:</label>
<input type="text" name="years"
value="<?php echo htmlspecialchars($years); ?>">
<br>
</div>
<div id="buttons">
<label> </label>
<input type="submit" value="Calculate"><br>
</div>
</form>
</main>
</body>
</html>
Trending now
This is a popular solution!
Step by step
Solved in 3 steps
