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I am working on a program that prints out the wages earned by workers including overtime pay. I am almost finished with the program. However, I am stuck on how to make a condition to fix the decimals in the wages to only the tenths and hundredths places (.00).

The condition I want is, if the number of hours worked is greater than 40 and the overtime wages have numbers in the thousandths place or more (overTimeWages has .000 or more .0000000000....), then System.out.println("$" + (Math.floor(overTimeWages * 100) / 100)); to round overTimeWages to the nearest hundredths down. I only want the tenths and hundredths place values. Else if hours worked is greater than 40 and the overtime wages have numbers only in the tenths and hundredths place, then System.out.println("$" + overTimeWages + 0);.

How do I make that condition above?

I tried overTimeWages % 0.1 != 0; but it did not work.

Below in the code comments are the values that are supposed to be inputted.

Code

import java.util.Scanner;

int payRateInCents, payRateInDollars,
    hoursWorked, 
    overTimeHours, grossPayWithInt;
  
double grossPay, payRCents, payRDollars, overTimeRate;

grossPay = (double) ((payRDollars * hoursWorked));
grossPayWithInt = (payRateInCents * 40);
double grossPayWithOverTime = (double) ((grossPayWithInt) + (overTimeRate * overTimeHours));
double overTimeWages = (double) (grossPayWithOverTime / 100);

/**
   2000 45 = (2000 * 40) + ((2000 * 1.5) * (45 - 40)) == 95000
   2000 45 = (grossPayWithOverTime) + ((overTimeRate) * (overTimeHours)) == 95000
   Then divide by 100.
   
   2000 40 should get: $800.00
   1640 41 should get: $680.60
   3111 43 should get: $1384.39
   1005 1 should get: $10.05
  **/

if(hoursWorked > 40) {
    if(overTimeWages % 0.1 != 0) {
      System.out.println("$" + (Math.floor(overTimeWages * 100) / 100));
    } else {
      System.out.println("$" + overTimeWages + 0);
    }
  }
  
  else {
    if(hoursWorked < 10) {
      System.out.println("$" + grossPay);
    } else {
      System.out.println("$" + grossPay + 0);//40 or lower
    }
  }
Aspiring_Coder
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    `double`s and `float`s don't always have exact values, so if you really care about sig figs and all, you might want to use something like `BigDecimal` – user Sep 30 '20 at 22:08
  • How do you use `BigDecimal` in an if statement? – Aspiring_Coder Sep 30 '20 at 22:51
  • What are you actually trying to do here? Testing "if it has more than 2 decimal places" is meaningless - it's a rendering issue, not a data issue. Do you want to *round* the value to at most 2 decimal places, or just display only 2, or what? – Bohemian Oct 01 '20 at 00:19

1 Answers1

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Dont use fractions or float for any variables that will hold money. Operations on float will give you unexpected result due to how floats are stored. You think 1.2 is 1.2 but it might be actually 1.19999999. That's how floats work. I would suggest to not get into any fractions when dealing with money. Instead of 1.30$ use 130 cents.

For displaying purposes converting it is trivial:

private static DecimalFormat df = new DecimalFormat("#.##");
Syste.out.println(df.format(yourDouble));

To see how many decimals number has.

String[] split = yourDouble.toString().split("\\.");
split[0].length();   
split[1].length();
JacekQ.
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  • Ok so DecimalFormat does about the same thing as BigDecimal but how would I fit this in my if else statement? I just want to check if my `overTimeWages` is past the thousandths place. – Aspiring_Coder Oct 01 '20 at 00:17
  • If you want to know how many decimals digits double has, you can convert it to String, split on '.' and check lenght. I edited the answer to include that code. – JacekQ. Oct 01 '20 at 00:38
  • Java outputed an error that says: "1 error found: Error: Cannot invoke toString() on the primitive type double" – Aspiring_Coder Oct 01 '20 at 00:46
  • `String.valueOf(yourDouble)` instead of `yourDouble.toString()` me thinks. – CryptoFool Oct 01 '20 at 00:54
  • For double (primitive) it's like Steve said (String.valueOf(yourDouble)). For Double (Object) you use yourDouble.toString() – JacekQ. Oct 01 '20 at 08:12