Solved

PHP calculate change

Posted on 2010-11-17
3
618 Views
Last Modified: 2012-05-10
I have a class called payment where I get the amount that a person owes then the amount the person paid then the amount of change. I also need to provide the a member function to determine the largest amount of each denomination to return to the customer. This is really confusing me I am not sure do I make a variable for each denomination. and then the math to figure out how to distribute it.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Calculate Change</title>
<meta http-equiv="content-type" content="text/html; charset=iso-8859-1" />
</head>
<body>

<?php



	class payment {

		public function __construct($paid,$owed) {
			$this->paid = $paid;
			$this->owed = $owed;
		}

		public function getChange() {
			return $this->owed - $this->paid;
		}

		public function getOwes() {
			return $this->owed - $this->paid;
		}
		public function returnDenomination(){
			
			$one = 1.00;
			$five = 5.00;
			$ten = 10.00;
			$twenty = 20.00;
			$fifty = 50.00;
			$hundred = 100.00;
			$penny = 0.01;
			$nickle = 0.05;
			$dime = 0.10;
			$quarter = 0.25;
			
			if(this->paid === this->owed)
			{
				echo "The customer is not owed any change. <br />"
			}
			else
			{
				return 
			



	}

	$payment = new payment($_POST["owed"],$_POST["paid"]);



	$change = $payment->getChange();
	$stillOwes = $payment->getOwes();


?>
<h1>Calculate Change</h1>
<h1>Enter a transaction</h1>
<form action="CalculateChange.php" method="post">
<table border="0">
     <tr><td align="right">Amount Owed:</td>

         <td align="left">$<input type="text" size="6" name="owed"
              value="" /></td></tr>
     <tr><td align="right">Amount Paid:</td>
         <td align="left">$<input type="text" size="6" name="paid"
              value="" /></td></tr>
<tr><td colspan="2" align="center">
     <input type="reset" name="reset" value="Clear Form" /> &nbsp;
     <input type="submit" name="submit" value="Calculate Change" /></td></tr>
</table>
</form>


</body>
</html>

Open in new window

0
Comment
Question by:rcham68
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
3 Comments
 
LVL 31

Expert Comment

by:Frosty555
ID: 34157675
The simplest way to calculate how to generate change is to start with the largest currency denomination, and subtract as many of those as you can until the amount of change you need to give is less than the denomination, then move down to the next largest currency denomination, and repeat until you get to pennies.

E.g. if you have to give $13.57 back in change, the way you do it is:

Denomination          #          Total          New Subtotal
$50 bills         -        0          $0                     $13.57
$20 bills         -        0          $0                     $13.57
$10 bills         -        1          $10                 $ 3.57
$5   bills         -         0         $0                    $3.57
$1   bills         -         3         $3                    $0.57
25c coins      -          2         $0.50              $0.07
10c coins     -          0          $0                    $0.07
5c   coins      -         1           $0.05              $0.02
1c   coins      -         2           $0.02              $0.00

Total:         1x $10 bill,   3x $1 bill,   2x 25c coin,   1x 5c coin,    2x 2c coin

0
 
LVL 31

Accepted Solution

by:
Frosty555 earned 500 total points
ID: 34157729
Pseudocode:

changetogive   =   13.57
twentybill = 0
tenbill = 0
fivebill = 0
onebill = 0
quarters = 0
dimes = 0
nickels = 0
pennies = 0

// 20 dollar bills
while changetogive >= 20 {
      changetogive -= 20
      twentybills += 1
}

// 10 dollar bills
while changetogive >= 10 {
      changetogive -= 10
      tenbills += 1
}

..... repeat for each type of currency ......

// nickels
while changetogive >= 0.05 {
      changetogive -= 0.05
      nickels += 1
}

// pennies
while changetogive >= 0.01 {
      changetogive -= 0.01
      pennies += 1
}


// finished!

total change to give is stored in the variables:

twentybill, tenbill,fivebill,
onebill, quarters, dimes,
nickels, pennies
0
 
LVL 19

Expert Comment

by:Michael701
ID: 34157764
gee, the 50¢ piece never gets any respect.


Have it return an array where the key is the denomination and the value is the quantity.

I know I'd give my students a few extra points for such an answer.
0

Featured Post

Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Since pre-biblical times, humans have sought ways to keep secrets, and share the secrets selectively.  This article explores the ways PHP can be used to hide and encrypt information.
Many old projects have bad code, but the budget doesn't exist to rewrite the codebase. You can update this code to be safer by introducing contemporary input validation, sanitation, and safer database queries.
The viewer will learn how to dynamically set the form action using jQuery.
The viewer will learn how to create and use a small PHP class to apply a watermark to an image. This video shows the viewer the setup for the PHP watermark as well as important coding language. Continue to Part 2 to learn the core code used in creat…

696 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question