CODEWITHSUNDEEP
java
ATGuy
ATGuy

Reputation: 13

Java - Else If loop will NOT work with instance variable

I'm attempting to calculate how much tax a user should pay, based on wage. For example, calculating 20% in the first if loop, this will be saved in generaltax:

    int generalTax = 0;
    int userGrossPay = 50000;
    if (userGrossPay <= 10600) {generalTax += 0;} 
    else if (((userGrossPay >= 10600) && (userGrossPay <= 31785))) { generalTax =  ((20/100) * userGrossPay); } 
    else if (((userGrossPay >= 31786) && (userGrossPay <= 150000))) { generalTax =  ((40/100) * userGrossPay); System.out.println(generalTax);} 
    else if (userGrossPay > 150001) {generalTax = ((45/100) * userGrossPay); }
    else{System.out.println("error");};

    userGrossPay -= generalTax;
    System.out.println(userGrossPay);

However generalTax pay is for some reason always stuck as 0 and is not properly updating on each iteration.

Upvotes: 1

Views: 55

Answers (2)

user3437460
user3437460

Reputation: 17454

This is caused by integer division.

If you mix floating data type with integer, it will give you a data conversion by promotion.

For example:

    int num = 5;
    System.out.println(num / 2);    //Gives you 2
    System.out.println(num / 2.0);  //Gives you 2.5
    System.out.println(num * 2);    //Gives you 10
    System.out.println(num * 2.0);  //Gives you 10.0
    System.out.println(num + 2.5);  //Gives you 7.5

If all operands in the operation are integers, your output will be integer as well. This is how you got into an integer division accidentally. 

((20/100) * userGrossPay);

I see that you already accepted Eran's answer and understood what went wrong, I am here to give you some additional information.

Upvotes: 0

Eran
Eran

Reputation: 393851

Your problem is that you are always adding 0 or assigning 0 to generalTax.

For example, (20/100) * userGrossPay is 0, since 20/100 is 0 due to int division. Change it too 0.2 * userGrossPay or 20.0/100 * userGrossPay. Similarly change all other places where you divide two integers.

Upvotes: 6

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