We Keep Coding

Why does my program only provide change in dollar amounts?

This is my current code:
import java.util.Scanner;
public class CustomerChange {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
double cost = 0.00;
double cash = 0.00;
double dollars = 0.00;
System.out.println("Price: ");
cost = scanner.nextDouble();
System.out.println("Cash: ");
cash = scanner.nextDouble();
if (cash < cost) {
System.out.println("Not enough cash. Goodbye.");
}
else if (cash > cost) {
dollars = cash - cost;
System.out.println("\nChange: \n");
if ((int) dollars / 20 > 0) {
System.out.println("Twenties: " + (int) dollars / 20);
dollars %= 20;
}
if ((int) dollars / 10 > 0) {
System.out.println("Tens: " + (int) dollars / 10);
dollars %= 10;
}
if ((int) dollars / 5 > 0) {
System.out.println("Fives: " + (int) dollars / 5);
dollars %= 5;
}
if ((int) dollars / 1 > 0) {
System.out.println("Ones: " + (int) dollars / 1);
dollars %= 1;
dollars *= 100;
}
if ((int) dollars / 25 > 0) {
System.out.println("Quarters: " + (int) dollars / 25);
dollars %= 25;
}
if ((int) dollars / 10 > 0) {
System.out.println("Dimes: " + (int) dollars / 10);
dollars %= 10;
}
if ((int) dollars / 5 > 0) {
System.out.println("Nickels: " + (int) dollars / 5);
}
if ((int) dollars / 1 > 0) {
System.out.println("Pennies: " + (int) dollars / 1);
}
} else if (cash == cost) {
System.out.println("Thank you. Goodbye.");
}
scanner.close();
}
}
Right now, when I enter in a price of 3.25 and a cash of 4, I don't get a return of my change, but when I enter in a price of 168.75 and a cash of 200, I get:
Price:
168.75
Cash:
200
Change:
Twenties: 1
Tens: 1
Ones: 1
Quarters: 1
Where am I going wrong? It took forever to figure out the math and I thought that was the crux but I guess not?

When you are inputting: Price: 3.25 and Cash: 4
(int)(0.75) will be 0.
So it will not get inside any of the if block.
Put a condition like
if ((int) dollars / 1 == 0) {
System.out.println("Pennies: " + (int)(dollars*100));
}
Then it will definitely work.

Your code is overly complicated due to attempting to work with double instead of just converting everything to an integer to begin with. This way everything is in the value of pennies, and you do not need to worry about any casting or multiplying a decimal later on by 100 in order to work with the coins, and the code will be less prone to bugs.
Here is what it would look like using similar logic you were using, but instead if in the form of pennies (you don't even need the if statements):
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
int pricePennies = 0;
int cashPennies = 0;
System.out.println("Price: ");
pricePennies = (int) (scanner.nextDouble() * 100);
System.out.println("Cash: ");
cashPennies = (int) (scanner.nextDouble() * 100);
if (cashPennies < pricePennies) {
System.out.println("Not enough cash. Goodbye.");
}
else if (cashPennies > pricePennies) {
int change = cashPennies - pricePennies;
System.out.println("Twenties: " + change / 2000);
change %= 2000;
System.out.println("Tens: " + change / 1000);
change %= 1000;
System.out.println("Fives: " + change / 500);
change %= 500;
System.out.println("Ones: " + change / 100);
change %= 100;
System.out.println("Quarters: " + change / 25);
change %= 25;
System.out.println("Dimes: " + change / 10);
change %= 10;
System.out.println("Nickels: " + change / 5);
change %= 5;
System.out.println("Pennies: " + change / 1);
change %= 1;
}
else if (cashPennies == pricePennies) {
System.out.println("Thank you. Goodbye.");
}
scanner.close();
}
Test Runs:
Price:
168.75
Cash:
200
Twenties: 1
Tens: 1
Fives: 0
Ones: 1
Quarters: 1
Dimes: 0
Nickels: 0
Pennies: 0
Price:
3.25
Cash:
4
Twenties: 0
Tens: 0
Fives: 0
Ones: 0
Quarters: 3
Dimes: 0
Nickels: 0
Pennies: 0
Price:
54748
Cash:
63939.46
Twenties: 459
Tens: 1
Fives: 0
Ones: 1
Quarters: 1
Dimes: 2
Nickels: 0
Pennies: 1

Trouble with the converting units

I am having a hard time understanding how to convert amounts such as $1.17 into this output:
1 dollar,
1 dime,
1 nickel,
2 pennies.
I need to use if statements which I can figure out but, the problem i am having is trying to get the change amounts to display correctly. Here is my code. I`m a visual learner so if you start me in the right direction that would be helpful.
import java.util.Scanner;
public class ComputeChange {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter an amount in double, for example 11.56: " );
double number = input.nextDouble();
System.out.println("Your amount " + number + " consists of ");
int Dollars = (int) (number);
int Quarters = Dollars / 25;
if (number == 1) {
System.out.print("1 dollar ");
}
else if (number > 1) {
System.out.print((int)Dollars + " dollars ");
}
if (number == 0) {
System.out.println("");
}
System.out.print( Quarters + " Quarters ");
}
}

You will probably want to use the modulus operator %. It is used with 2 numbers and returns the remainder of a divided by b where a is the left hand assignment and b is the right hand represented like a%b.
Example:
11%2=1 explanation: 5*2 = 10, 11-10 = 1
.66%.25=.16 explanation: 2*.25 = .5, .66-.5=.16
Start with a simple problem where you only have 2 types of coins, say 8¢ or $0.08.
double monies = .08;
int numNickles = (int)(monies/.05) = 1 // one nickle
monies = monies % .05; // or you can write as monies %=.05;
// monies value should now be .03
int numPennies = (int)(monies/.01) = 3 // three pennies

A much simpler approach than using modulus is to calculate the units of measurement in top-down fashion (from the highest to the lowest) and keep deducting them from the total already converted into the lowest unit.
A lot of libraries use this approach with units of time as well i.e. converting a time span into hours, minutes and seconds. Here's the same approach for currency. I've added inline comments to explain the code as best as possible.
// Scan the amount
Scanner scanner = new Scanner(System.in);
System.out.print("Enter amount: ");
double amount = scanner.nextDouble();
scanner.close();
// convert into cents
int cents = (int) (amount * 100);
// get dollars
int dollars = cents/100;
// cents left after dollars
cents = cents - dollars*100;
// get quarters
int quaters = cents/25;
// cents left after quarters
cents = cents - quaters*25;
// get dimes
int dimes = cents/10;
// cents left after dimes
cents = cents - dimes*10;
// get nickels
int nickels = cents/5;
// cents left after nickels
cents = cents - nickels*5;
// leftover cents are pennies
int pennies = cents;
Now, just build the output message with a StringBuilder as
StringBuilder msg = new StringBuilder("You have:");
if (dollars > 0) {
msg.append(" ").append(dollars).append(" dollar").append(dollars > 1 ? "s" : "");
}
if (quaters > 0) {
msg.append(" ").append(quaters).append(" quarter").append(quaters > 1 ? "s" : "");
}
if (dimes > 0) {
msg.append(" ").append(dimes).append(" dime").append(dimes > 1 ? "s" : "");
}
if (nickels > 0) {
msg.append(" ").append(nickels).append(" nickel").append(nickels > 1 ? "s" : "");
}
if (pennies > 0) {
msg.append(" ").append(pennies).append(" pennie").append(pennies > 1 ? "s" : "");
}
System.out.println(msg);
Output :
Enter amount: 1.17
You have: 1 dollar 1 dime 1 nickel 2 pennies
Enter amount: 12.99
You have: 12 dollars 3 quarters 2 dimes 4 pennies

Odd accuracy error Java

Currently I am attempting to write a change machine in java. For some reason there is a large loss in accuracy during conversion.
It will first ask for the data values of how much is owed and how much is paid. Then it will divide out the numbers of quarters and mod out the remainder. Then it will perform this with dimes, nickles, and then pennies. After this it will then print out how much change is owed.
import java.io.*;
import static java.lang.System.*;
import java.util.Scanner;
class change{
public static void main (String str[]) throws IOException {
//asker thingy
Scanner scan = new Scanner(System.in);
System.out.println("Please enter the Cost of the Item:");
System.out.print("$");
double costowed = scan.nextDouble();
System.out.println("Please Enter the Amount Payed:");
System.out.print("$");
double costpayed = scan.nextDouble();
//Quarters
double a1 = Math.round( (costpayed - costowed) * 100);
int quarters = (int)(a1 / 25);
int a2 = (int)(a1 % 25);
//dimes
int dimes = (int)(a2 / 10);
int a3 = (int)(a1 % 10);
//nickles & pennies
int nickles = (int)(a3 / 5);
int pennies = (int)(a1 % 5);
//change owed
double arc = (double)(a1 / 100);
//print sequence
System.out.println("Change owed: " + arc);
System.out.println("Quarters: " + quarters);
System.out.println("Dimes: " + dimes);
System.out.println("Nickles: " + nickles);
System.out.println("Pennies: " + pennies);
}
}

The line
int a3 = (int)(a1 % 10);
should be:
int a3 = (int)(a2 % 10);
And likewise int pennies = (int)(a1 % 5); should be int pennies = (int)(a3 % 5);.

Java - Assigning User Input to Variable / Change Counter

I'm quite new to java, although I have a fairly basic knowledge of C++.
For my assignment I am counting change and sorting it into American currency (i.e., if you had 105 cents, it would divide it into one dollar and one dime).
Logically I understand how to do this, but I'm having some serious trouble understanding the java syntax. I'm having serious trouble to find a way to assign a user-inputted value to a variable of my creation. In C++ you would simply use cin, but Java seems to be a lot more complicated in this regard.
Here is my code so far:
package coinCounter;
import KeyboardPackage.Keyboard;
import java.util.Scanner;
public class helloworld
{
public static void main(String[] args)
{
Scanner input new Scanner(System.in);
//entire value of money, to be split into dollars, quarters, etc.
int money = input.nextInt();
int dollars = 0, quarters = 0, dimes = 0, nickels = 0;
//asks for the amount of money
System.out.println("Enter the amount of money in cents.");
//checking for dollars, and leaving the change
if(money >= 100)
{
dollars = money / 100;
money = money % 100;
}
//taking the remainder, and sorting it into dimes, nickels, and pennies
else if(money > 0)
{
quarters = money / 25;
money = money % 25;
dimes = money / 10;
money = money % 10;
nickels = money / 5;
money = money % 5;
}
//result
System.out.println("Dollars: " + dollars + ", Quarters: " + quarters + ", Dimes: " + dimes + ", Nickels: " + nickels + ", Pennies: " + money);
}
}
I would really appreciate some help with how to assign a user-input to my variable, Money. However, if you see another error in the code, feel free to point it out.
I know this is really basic stuff, so I appreciate all of your cooperation.

Change this line :
Scanner input new Scanner(System.in);
To :
Scanner input = new Scanner(System.in);
And this should be after line below not before:
System.out.println("Enter the amount of money in cents.");
And as you did , the line below will read from input int value and assign it to your variable money :
int money = input.nextInt();

min change greedy algorithm in java

Ok so i need to make a program to ask me for an amount of money, then I need it to tell me the least amount of coins to make it. The coins I can use are: dollars, quarters, dimes, nickels, and pennies. For example, When I run the program it's supposed to look like this:
> run Coins
Enter the amount of given money:
[1.73]
Give the seller 8 coins:
1 dollars,
2 quarters,
2 dime,
0 nickels,
3 pennies.
This is What I have so far:
import java.util.Scanner;
class Coins {
public static void main (String args[]) {
Scanner input = new Scanner(System.in);
double money;
System.out.println("Enter the amount of money ");
money = input.nextDouble();
while (money > 0.0 ){
if (money >= 1) {
System.out.println(money/1+"dollars");
money -= 1;
}
else if (money>=.25) {
System.out.println(money/.25+"quarters");
money-=.25;
}
else if (money>=.10) {
System.out.println(money/.10+"Dimes");
money-=.10;
}
else if (money>=.05) {
System.out.println(money/.05+"Nickels");
money-=.05;
}
else if (money>=.01) {
System.out.println(money/.01+"Penny");
money-=.01;
}
}
}
}
The part I need help with is this: If I run the program and enter the amount 1.73, the way I have the code written, it takes the number 1.73, divides it by 1, and prints "1.73 dollars". I need a way to get rid of the decimal part so instead of printing "1.73 dollars", it prints "1 dollar". But I'm not sure how to do this. I tried converting it to an int but it messes up the flow of the other statements. Please help me.

You should use the combination of floor with casting to double, the following code works:
class Coins {
public static void main (String args[]) {
double money = 1.73;
while (money > 0.0 ){
if (money >= 1) {
System.out.println(Math.floor(money/1)+" dollars");
money -= Math.floor(money/1)*(double)1;
}
else if (money>=.25) {
System.out.println(Math.floor(money/.25)+" quarters");
money-=Math.floor(money/.25)*(double).25;
}
else if (money>=.10) {
System.out.println(Math.floor(money/.10)+" Dimes");
money-=Math.floor(money/.10)*(double).10;
}
else if (money>=.05) {
System.out.println(Math.floor(money/.05)+" Nickels");
money-=Math.floor(money/.05)*(double).05;
}
else if (money>=.01) {
System.out.println(Math.round(money/.01)+" Penny");
money-=Math.round(money/.01)*(double).01;
}
}
}
}
Another bug you had:
You should subtract Math.floor(money/XXX)*(double)XXX not (double)XXX

You need get rid of the remainder after the divisions. You can use Math.floor() for this:
class Coins {
public static void main (String args[]) {
double money = 1.73;
int dollars = (int) Math.floor(money/1);
money -= dollars * 1;
int quarters = (int) Math.floor(money/0.25);
money -= quarters * 0.25;
int dimes = (int) Math.floor(money/0.10);
money -= dimes * 0.10;
int nickels = (int) Math.floor(money/0.05);
money -= nickels * 0.05;
int pennies = (int) Math.round(money * 100);
System.out.println("Dollars: " + dollars);
System.out.println("Quarters: " + quarters);
System.out.println("Dimes: " + dimes);
System.out.println("Nickels: " + nickels);
System.out.println("Pennies: " + pennies);
}
}
Resulting in:
Dollars: 1
Quarters: 2
Dimes: 2
Nickels: 0
Pennies: 3