Java - Abstract Classes - Values not registering in 'extended' class-CodePudding

I wrote a Java coding using Abstraction OOP to calculate federal and state income tax from a salary.

The code is below. `

import java.util.Scanner;

abstract class USA_Tax{
    protected final double income_tax = 0.15;
    protected double pre_tax_amount;
    protected double tax_to_fed;

    public void federal_tax(){
        Scanner input = new Scanner (System.in);
        System.out.println ("Enter pre-tax income: ");
        double pre_tax_amount = input.nextDouble();
        System.out.println ("Money owned to federal government: ");
        tax_to_fed = (double)(pre_tax_amount*0.15);
        System.out.println (tax_to_fed);
    input.close();
    }
}

class California_Tax extends USA_Tax{
    protected final double ca_income_tax = 0.10;
    protected double after_california_tax;
    protected double total_money_left;
    public void ca_tax(){
        after_california_tax = (double)(pre_tax_amount * ca_income_tax);
        System.out.println("Money owned to CA government: "   after_california_tax);
        total_money_left = (pre_tax_amount) - (after_california_tax   tax_to_fed);
        System.out.println ("Total take home:"   total_money_left);
    }    
}

public class class_abstraction{
    public static void main (String[] args){

        California_Tax tax1 = new California_Tax();
        tax1.federal_tax();
        tax1.ca_tax();
    }
}

However, when I run the code, only values from the abstract class seem to pop up correctly. The values for the after_california_tax and total_money_left variables in the extended class show up as 0.0. Below is an example output

Enter pre-tax income: 100000 Money owned to federal government: 15000.0 Money owned to CA government: 0.0 Total take home:-15000.0

I also tried to remove 'abstract' from the first class but nothing changed.

Could someone help me understanding what I am doing wrong?

I was expecting correct number outputs. I tried to remove 'abstract' from the first class but nothing changed.

CodePudding user response：

In public void federal_tax(), you redefine the variable pre_tax_amount:

double pre_tax_amount = input.nextDouble();

You are thus not using the member variable defined above. You need to assign the value in the already declared variable:

pre_tax_amount = input.nextDouble();

CodePudding user response：

This is where you have messed up, you have created a new local variable which was not required, use the instance variable instead which you have defined.

double pre_tax_amount = input.nextDouble();

Code after the change is done

    import java.util.Scanner;

abstract class USA_Tax{
    protected final double income_tax = 0.15;
    protected double pre_tax_amount;
    protected double tax_to_fed;

    public void federal_tax(){
        Scanner input = new Scanner (System.in);
        System.out.println ("Enter pre-tax income: ");
        pre_tax_amount = input.nextDouble();
        System.out.println ("Money owned to federal government: ");
        tax_to_fed = (double)(pre_tax_amount*0.15);
        System.out.println (tax_to_fed);
    input.close();
    }
}

class California_Tax extends USA_Tax{
    protected final double ca_income_tax = 0.10;
    protected double after_california_tax;
    protected double total_money_left;
    public void ca_tax(){
        after_california_tax = (double)(pre_tax_amount * ca_income_tax);
        System.out.println("Money owned to CA government: "   after_california_tax);
        total_money_left = (pre_tax_amount) - (after_california_tax   tax_to_fed);
        System.out.println ("Total take home:"   total_money_left);
    }    
}

public class test{
    public static void main (String[] args){

        California_Tax tax1 = new California_Tax();
        tax1.federal_tax();
        tax1.ca_tax();
    }
}