Java: Order of Operations Unclear

Question

First question:

I wrote a program to calculate gift tax. When tested with input value: 14491 the output was -25436.3. I can't figure out how this number was calculated. Can anyone help explain this? If I'm not mistaken the code should have calculated parentheses then multiplied and then added. I'm also a noob, so I'm probably wrong but would love feedback.

Second question:

Is there a better way to have written this code?

import java.util.Scanner;
 
public class GiftTax {
 
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
 
        System.out.println("Value of the gift?");
        double amt = scan.nextDouble();
 
        if (amt < 5000) {
            System.out.println("No tax!");
        } else if (amt == 5000 && amt <= 25000) {
            System.out.println("Tax: " + (100 + (amt - 5000) * .08));
        } else if (amt == 25000 && amt <= 55000) {
            System.out.println("Tax: " + (1700 + (amt - 25000) * .10));
        } else if (amt == 55000 && amt <= 200000) {
            System.out.println("Tax: " + (4700 + (amt - 55000) * .12));
        } else if (amt == 200000 && amt <= 1000000) {
            System.out.println("Tax: " + (22100 + (amt - 200000)* .15));
        } else {
            System.out.println("Tax: " + (142100 + (amt - 1000000) * .17));
        }
    }
}

I changed "==" in the code to ">=" and it worked perfectly. I just don't understand how it came up with that initial negative number and it's driving me mad...

Thanks everyone!

Answer 1

I just don't understand how it came up with that initial negative number and it's driving me mad...

Since 14491 is not less than 5000, it runs through all the else/if checks but 14491 is not EXACTLY equal to 5000, 25000, 55000, or 200000, so only the LAST ELSE block is what gets executed:

} else {
    System.out.println("Tax: " + (142100 + (amt - 1000000) * .17));
}

The calculation is:

(142100 + (amt - 1000000) * .17)
(142100 + (14491- 1000000) * .17)
(142100 + (-985,509) * .17)
(142100 + (-167,536.53))
-25,436.53