$value ";
} // End of create_radio() function.
// This function calculates the cost of the trip.
// The function takes three arguments: the distance, the fuel efficiency, and the price per gallon.
// The function returns the total cost.
function calculate_trip_cost($miles, $mpg, $ppg) {
// Get the number of gallons:
$gallons = $miles/$mpg;
// Get the cost of those gallons:
$dollars = $gallons/$ppg;
// Return the formatted cost:
return number_format($dollars, 2);
} // End of calculate_trip_cost() function.
$page_title = 'Trip Cost Calculator';
include ('includes/header.html');
// Check for form submission:
if ($_SERVER['REQUEST_METHOD'] == 'POST') {
// Minimal form validation:
if (isset($_POST['distance'], $_POST['gallon_price'], $_POST['efficiency']) &&
is_numeric($_POST['distance']) && is_numeric($_POST['gallon_price']) && is_numeric($_POST['efficiency']) ) {
// Calculate the results:
$cost = calculate_trip_cost($_POST['distance'], $_POST['efficiency'], $_POST['gallon_price']);
$hours = $_POST['distance']/65;
// Print the results:
echo 'Total Estimated Cost
The total cost of driving ' . $_POST['distance'] . ' miles, averaging ' . $_POST['efficiency'] . ' miles per gallon, and paying an average of $' . $_POST['gallon_price'] . ' per gallon, is $' . $cost . '. If you drive at an average of 65 miles per hour, the trip will take approximately ' . number_format($hours, 2) . ' hours.
';
} else { // Invalid submitted values.
echo 'Error!
Please enter a valid distance, price per gallon, and fuel efficiency.
';
}
} // End of main submission IF.
// Leave the PHP section and create the HTML form:
?>
Trip Cost Calculator