Thread: Mathematical problem with Money amounts

Hi All,
And first of all thanks for taking the time to read my first post.

I am working through a a java textbook and am stuck on this application problem :

 
 
"Write an application that prompts for and reads a double value representing a monetary amount. Then determine the fewest number of each bill and coin needed to represent that amount, starting with the highest (assume that a ten dollar bill is the maximum size needed). For example, if the value entered is $47.63, then the program should print the equivalent amount as:
 4 ten dollar bills 
 1 five dollar bills
 2 one dollar bills
 2 quarters
 1 dimes
 0 nickels
 3 pennies   "
 
I have tackled it by using starting with a total amount (eg 5678 dollars) and using division followed by remainder operator to work down to dollars then cents. (I am working in 10dollarnotes, 5dollarnotes, 1dollarcoin, 2dollarcoin, 10centpice and 20centpiece rather than the currency in the example).
 
I have found this to work in easier examples but I'm hopeful there is a better way..... At the moment it prints the correct value of 10dollar notes, but FAR too many 2dollarcoins and NaN for cents. Also it doesnt allow me to scan the total so I can enter and rerun with a new total for the terminal. Here is what i'm puttin in and getting out :
 
 
//RevCoinValueScan.java
//application which prompts for and reads a monetary amount in dollars 
//and cents. Then determines the fewest amount of 10dollar, 5dollar
//notes,
//5,10 cent 1 and 2dollar coins required to make that amount.
 
import java.util.Scanner;
 
public class RevCoinValueScan
{
public static void main (String[] args)
{
  double note10;
  double dollar2;
  double dollar1;
  double cent10;
  double cent5;
 
  double total = 5678; 
  double total2; 
  double total3;
  double total4;
  double total5;
 
  Scanner scan = new Scanner (System.in);
 
  System.out.println ("Enter the monetary amount: " + total);
 
   note10 = total / 10;
   total2 = total % note10;
   dollar2 = total2 / 2;
   total3 = total2 % dollar2;
   dollar1 = total3 / 1;
   total4 = total3 % dollar1;
   cent10 = total4 / 0.10;
   total5 = total4 % cent10;
   cent5 = total5 / 5;
 
  System.out.println (" the total number of 10 dollar notes is: " + note10);
  System.out.println (" Two Dollar coins: " + dollar2);
  System.out.println (" One Dollar coins: " + dollar1);
  System.out.println (" Ten Cent coins: " + cent10);
  System.out.println (" Five Cent coins: " + cent5);
 
   }
}

AND HERES WHAT I'M GETTING OUT :

 
1 error
craig@craig-laptop:~/Documents/panda/java$ javac RevCoinValueScan.java
craig@craig-laptop:~/Documents/panda/java$ java RevCoinValueScan
Enter the monetary amount: 5678.0
 the total number of 10 dollar notes is: 567.8
 Two Dollar coins: 2.2737367544323206E-13
 One Dollar coins: 0.0
 Ten Cent coins: NaN
 Five Cent coins: NaN
craig@craig-laptop:~/Documents/panda/java$ 
 
 
ANOTHER AMOUNT : 
 
craig@craig-laptop:~/Documents/panda/java$ javac RevCoinValueScan.java
craig@craig-laptop:~/Documents/panda/java$ java RevCoinValueScan
Enter the monetary amount: 786.908
 the total number of 10 dollar notes is: 78.6908
 Two Dollar coins: 2.8421709430404007E-14
 One Dollar coins: 0.0
 Ten Cent coins: NaN
 Five Cent coins: NaN
craig@craig-laptop:~/Documents/panda/java$

what the hell? It worked then i tried editing again and my whole post disappeared

Thanks Norm. I am not sure how to print out the values of the totalX variables but I will give it a try now:

  double total = 786.908; 
  double total2; 
  double total3;
  double total4;
  double total5;
 
 <script language="javascript">
var total2
document.write (total2); //prints the value of total2
</script> 
 
 <script language="javascript">
total3
document.write (total3); //prints the value of total3
</script> 
 
 <script language="javascript">
total4
document.write (total4); //prints the value of total4
</script> 
 
 <script language="javascript">
total5
document.write (total5); //prints the value of total5
</script>

I JUST ENTERED THAT HALFWAY DOWN DOWN THE PROGRAM AFTER THE BIT WHERE YOU DECLARE THE NUMBERS AS 'DOUBLES'.

AND GOT THIS RESULT :

RevCoinValueScan2.java:25: error: > expected
 <script language="javascript">
         ^
RevCoinValueScan2.java:26: error: ';' expected
var total2
   ^
RevCoinValueScan2.java:27: error: ';' expected
document.write (total2); //prints the value of total2
        ^
RevCoinValueScan2.java:28: error: illegal start of type
</script> 
 ^
RevCoinValueScan2.java:28: error: illegal start of expression
</script> 
  ^
RevCoinValueScan2.java:30: error: > expected
 <script language="javascript">
         ^
RevCoinValueScan2.java:31: error: ';' expected
total3
      ^
RevCoinValueScan2.java:33: error: illegal start of type
</script> 
 ^
RevCoinValueScan2.java:33: error: illegal start of expression
</script> 
  ^
RevCoinValueScan2.java:35: error: > expected
 <script language="javascript">
         ^
RevCoinValueScan2.java:36: error: ';' expected
total4
      ^
RevCoinValueScan2.java:38: error: illegal start of type
</script> 
 ^
RevCoinValueScan2.java:38: error: illegal start of expression
</script> 
  ^
RevCoinValueScan2.java:40: error: > expected
 <script language="javascript">
         ^
RevCoinValueScan2.java:41: error: ';' expected
total5
      ^
RevCoinValueScan2.java:43: error: illegal start of type
</script> 
 ^
RevCoinValueScan2.java:43: error: illegal start of expression
</script> 
  ^
RevCoinValueScan2.java:43: error: not a statement
</script> 
        ^
RevCoinValueScan2.java:45: error: ';' expected
  Scanner scan = new Scanner (System.in);
         ^
19 errors
craig@craig-laptop:~/Documents/panda/java$

Firstly, try and make variable names that make better sense. dollar1 and dollar2 are not the best names. There are far too many totals as well.

Are you trying to divide the money by the largest denomination (/ divide) and then continue using the remainder to divide by the next one down? Maybe set up some sort of 'fall-through' system in your code. Like a switch with no break.

Ok firstly thank you for your replies Norm and Starstreak. And secondly please excuse me for responding infrequently to this thread because I have very limited internet connection at the moment due to my landlord. Anyway..
Norm I'm not too sure what you mean by 'javascript code in the java code' - I think a few posts in this thread have disappeared because I tried something yesterday that you had recommended me I think - but I wasnt too sure what I was doing anyway.
I will investigate a switch with no break and get back to you.
Thanks guys

--- Update ---

Originally Posted by Starstreak

Are you trying to divide the money by the largest denomination (/ divide) and then continue using the remainder to divide by the next one down?

Yes that is precisely what i'm doing. I knew when I started that it surely isnt the best way to go about it. But its the only method I knew.