[hardwired]

Code:

import java.util.Scanner;

public class Q2P {
    public void start(){
        // User types in income to nearest dollar and program
        // responds with tax owing, and tax as % of income
        // Ignore the under $9,880 rebate
        // Assume all income counts for the "under $38,000" rebate
        // Show with, and without, student loan owing for the entire year
        // Use double arithmetic for calculations, but..
        // Display money amounts rounded to nearest dollar
        // Make use of the following constants for the tax rates

        final double LOW_TAX_RATE = 0.195;
        final double MID_TAX_RATE = 0.33;
        final double TOP_TAX_RATE = 0.39;
        final double REBATE_RATE = 0.045;
        final double PENALTY_RATE = 0.015;
        final double LOAN_RATE = 0.1;

        /* Note that a professional program would also use constants for the
           various income levels, but that would make this exercise a bit
           cumbersome for beginners */

        //Scanner scanner = new Scanner(System.in);
        // Get income from the user
        System.out.print("Type in total income to nearest dollar: ");
        String in = Keyboard.readInput();
                    //scanner.nextLine();
        double income = Double.parseDouble(in);

        double under38000 = Math.min(income, 38000);
        System.out.println("On a income of: $" + Math.round(under38000));

        double over38000 = Math.max(0,income - 38000);
        System.out.println("On a income of: $" + Math.round(over38000));

        double inBetween = over38000 - Math.max(0, income - 60000);
        System.out.println("On a income of: $" + Math.round(inBetween));

        double over60000 = Math.max(0, income - 60000);
        System.out.println("On a income of: $" + Math.round(over60000));


        // Calculate income tax
        // find tax on income up to $38,000 at 19.5%
        double under38000Tax = under38000 * LOW_TAX_RATE;
        System.out.println(" Income tax is: $" + Math.round(under38000Tax));

        // find tax on income between $38,000 and $60,000 at 33%
        double inBetweenTax = inBetween * MID_TAX_RATE;
        System.out.println(" Income tax is: $" + Math.round(inBetweenTax));

        // find tax on income over $60,000 at 39%
        double over60000Tax = over60000 * TOP_TAX_RATE;
        System.out.println(" Income tax is: $" + Math.round(over60000Tax));

        // Calculate tax rebate
        // find rebate on income up to $9500 at 4.5%
        double taxRebate = 9500 * REBATE_RATE;

        // find penalty on rebate for income between $9500 and $38,000 at 1.5%
        // income between $9500 and $38,000 = incomeOver9500 - incomeOver38000
        double over9500 =  Math.max(0, income - 9500);
        System.out.printf("income = %.0f  over9500 = %.0f  over38000 = %.0f%n" +
                          "income between $9500 and $38,000 = %.0f%n",
                           income, over9500, over38000, over9500 - over38000);
        double penaltyRebate = (over9500 - over38000) * PENALTY_RATE;

        // calculate net rebate
        double netRebate = (taxRebate - penaltyRebate);

        // calculate total income tax
        double totalUnder38000Tax = (under38000 - under38000Tax);
        double totalInBetweenTax = (inBetween - inBetweenTax);
        double totalOver60000Tax = (over60000 - over60000Tax);

        // Calculate percentage of income
        double percentUnder38000 = ((under38000 - totalUnder38000Tax) * 100);
        double percentInBetween = ((inBetween - totalInBetweenTax) * 100);
        double percentOver60000 = ((over60000 - totalOver60000Tax) * 100);

        // Calculate student loan tax
        double studentLoanTax = (income - 17160) * LOAN_RATE;

        // Calculate total taxes, with and without loan;
        double totalTax = (totalUnder38000Tax + totalInBetweenTax +
                           totalOver60000Tax - netRebate);
        double totalTaxInclStudentLoan = (totalTax + studentLoanTax);

        // Display tax owing and rates
        // Use the method Math.round() to convert a double value
        // to the nearest whole dollar value.
        System.out.println(" With rebate of: " + Math.round(netRebate));
        System.out.println(" Giving total tax of: " + Math.round(totalTax));
        System.out.println(" Which is: " + Math.round(percentUnder38000) + " of income");
        System.out.println(" Which is: " + Math.round(percentInBetween) + " of income");
        System.out.println(" Which is: " + Math.round(percentOver60000) + " of income");
        System.out.println("With a student loan:");
        System.out.println(" Loan repayment is an additional: " +
                             Math.round(studentLoanTax));
    }

    public static void main(String[] args) { new Q2P().start(); }
}