Solved

PHP calculate change

Posted on 2010-11-17
3
594 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
  • 2
3 Comments
 
LVL 31

Expert Comment

by:Frosty555
Comment Utility
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
Comment Utility
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
Comment Utility
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

How your wiki can always stay up-to-date

Quip doubles as a “living” wiki and a project management tool that evolves with your organization. As you finish projects in Quip, the work remains, easily accessible to all team members, new and old.
- Increase transparency
- Onboard new hires faster
- Access from mobile/offline

Join & Write a Comment

Suggested Solutions

Title # Comments Views Activity
creating 2 user ID's 5 24
Should you use {} for a variable in heredoc 3 24
How do I edit this Drupal page? 9 26
sql sentence 2 10
Popularity Can Be Measured Sometimes we deal with questions of popularity, and we need a way to collect opinions from our clients.  This article shows a simple teaching example of how we might elect a favorite color by letting our clients vote for …
This article discusses four methods for overlaying images in a container on a web page
The viewer will learn how to dynamically set the form action using jQuery.
The viewer will learn how to create a basic form using some HTML5 and PHP for later processing. Set up your basic HTML file. Open your form tag and set the method and action attributes.: (CODE) Set up your first few inputs one for the name and …

772 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

Need Help in Real-Time?

Connect with top rated Experts

11 Experts available now in Live!

Get 1:1 Help Now