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(COMPLETE newbie here). I've got an extra sheet with simple exercises to complete. One of the exercises says to write a program where user can input a random amount of money and the program tells the user how many euros, 50 cents, 20 cents, 10 cents, 5 cents, 2 cents and 1 cents are needed to make up the amount entered. I try to use the modulus to get the amount of cents needed,

My question is how do I get my program to calculate the number of CENTS needed? Everytime I use division operator to get the number of 50 cents needed on the remainder of the amount (ex. 0.60) it rounds the double up giving me 2 as output.

Scanner keyboard = new Scanner(System.in);

System.out.print("Input money recieved: ");
double recieve = keyboard.nextDouble();

double cents = recieve * 100;

int centsTotal = (int)cents;

System.out.print("Cents in total " + centsTotal);

int notes = centsTotal / 100;

System.out.print("\nEuros: " + notes);

double remain = recieve % notes;

System.out.printf("\nRemain: %.2f",remain);

double remain2 = remain / 0.5;

System.out.println("\nTest: ",remain2);

My output is: 

Input money recieved: 45,78
    Cents in total 4578
    Euros: 45
    Remain: 0,78
    Test: 1.5600000000000023
G. Martyna
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  • check out : http://stackoverflow.com/questions/703396/how-to-nicely-format-floating-numbers-to-string-without-unnecessary-decimal-0 – dima Sep 25 '16 at 19:57
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    Also, floating point is not exact, so normally one does math for currencies in integers (say in cents, where you typically don't need to round) and then either print out as a decimal or do your own print routine. – markspace Sep 25 '16 at 20:00

2 Answers2

1

You can cheat by using the Math.round() function like so:

double roundOff = Math.round(valueToRound * 100.0) / 100.0;

This ensures that you keep the value as a double, which allows you to do further operations on it if necessary.

ahjohnston25
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0

One way is maybe a little brutal, but memory efficient (create no new object or variables). Simply cast your double to int to round down.

public class RoundingTest {
  public static void main(String[] args) {
    double num = 1.56;
    System.out.println("Test: " + (int)num);
  }
}

Outputs:

Test: 1

This also allows you to keep your original double untouched for further calculation if needed.

NonCreature0714
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