Comp Sci How can I fix my Java program to give accurate change?

  • Thread starter Thread starter willie9142002
  • Start date Start date
  • Tags Tags
    Code Java
AI Thread Summary
The Java program aims to calculate and display the correct change for a randomly generated amount, but it struggles with accurately counting pennies. The current logic leads to repeated outputs when multiple pennies are needed, indicating a flaw in the change calculation process. To resolve this, the program should prioritize subtracting the largest denominations first (quarters, then dimes, then nickels, and finally pennies) without prematurely printing the output. The discussion suggests considering modular arithmetic to simplify the code and improve accuracy. Overall, a more structured approach to handling the change calculation is necessary for the program to function correctly.
willie9142002
Messages
2
Reaction score
0
I had to write a java program that will give you the change for whatever random number that program picks. I keep having a problem with the pennies. If have to have more than one penny then program will repeat the output until it gets the pennines right. PLEASE HELP! I am not really good at Java so the program my look really bad please help!

import javax.swing.*;
public class CoinCounter
{

public static void main(String[] args)
{
int quarter = 25;
int dime = 10;
int nickel = 5;
int penny = 1;
int numQuarters = 0;
int numDimes = 0;
int numNickels = 0;
int numPennies = 0;



int r = (int)(Math.random() * 99);
int changeRequired = r;

while(changeRequired > 0){

if(changeRequired - quarter>= 0){
numQuarters ++;
changeRequired -= quarter;
continue;
}
if(changeRequired - dime >= 0){
numDimes ++;
changeRequired -= dime;
continue;
}
if(changeRequired - nickel >= 0){
numNickels ++;
changeRequired -= nickel;
continue;
}
if(changeRequired - penny >= 0){
numPennies ++;
changeRequired -= penny;

System.out.println("Your change is: " + r );
System.out.println(numQuarters+" Quarters");
System.out.println(numDimes+" Dimes");
System.out.println(numNickels+" Nickels");
System.out.println(numPennies+" Pennies");
}
}
}
}

Here is the output:
Your change is: 43
1 Quarters
1 Dimes
1 Nickels
1 Pennies
Your change is: 43
1 Quarters
1 Dimes
1 Nickels
2 Pennies
Your change is: 43
1 Quarters
1 Dimes
1 Nickels
3 Pennies

Process completed.
 
Physics news on Phys.org
The pennies is the "catch all" condition. I suspect if you used larger change amounts that your program would produce unexpected results. For example, 62 cents will return most likely something other than 2 quarters, 1 dime and 2 pennies (probably 1 quarter, 2 dimes, 3 nickels and 2 pennies). Using your logic, what you SHOULD do is keep subtracting quarters until you can subtract no more, then dimes, then nickels and the remainder must be pennies finally. Do you know about modular arithmetic? You can seriously do the entire program in 1 line of code with it.
 
Last edited:
jhicks
even with higher amounts is does that same thing only if i need more than one penny. So if it is was 62 it would give me 2 quarters, 1 dime, 1 penny then 2 quarters, 1 dime, 2 pennies. See my problem? How do I keep subtracting quarters until there are no more than dime and so on??!? I am really new and I am struggling to do this right. I have no clue what modular arithmetic is I am a 28 year old college freshman sationed overseas trying to get a degree so any help, books, or websites I should read would be a great help thanks in advance
 

Similar threads

Replies
7
Views
3K
Replies
1
Views
2K
Replies
2
Views
1K
Replies
12
Views
2K
Replies
5
Views
3K
Replies
1
Views
2K
Replies
2
Views
4K
Back
Top