Implementing Icomparable on a Taxpayer class to sort based on taxOwed

Question

i am not being able to implemenet Icomparable CompareTo to compare Taxpayer objects based on tax owed ..can someone help me with the icomparable implementatioin of Taxpayer class?? I want to implement the icomparable like here-Interfaces is new topic to me..please help http://www.dotnetperls.com/icomparable

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Taxes
{
    class Rates
    {
        // Create a class named rates that has the following data members: 
        private int incomeLimit;
        private double lowTaxRate;
        private double highTaxRate;

        public int IncomeLimit  // use read-only accessor.
        { get { return incomeLimit; } }

        public double LowTaxRate // use read-only accessor.
        { get { return lowTaxRate; } }

        public double HighTaxRate // use read-only accessor.
        { get { return highTaxRate; } }

        //A class constructor that assigns default values of limit=30000, low rate = .15 and high rate = .28.
        public Rates()
        {
            int limit = 30000;
            double lowRate = .15;
            double highRate = .28;

            incomeLimit = limit;
            lowTaxRate = lowRate;
            highTaxRate = highRate;
        }

        //A class constructor that takes three parameters to assign input values for limit, low rate and high rate.
        public Rates(int limit, double lowRate, double highRate)
        {

        }

        //  A CalculateTax method that takes an income parameter and computes the tax as follows:
        public int CalculateTax(int income)
        {
            int limit = 0;
            double lowRate = 0;
            double highRate = 0;
            int taxOwed = 0;

            //  If income is less than the limit then return the tax as income times low rate.
            if (income < limit)
                taxOwed = Convert.ToInt32(income * lowRate);
            //  If income is greater than or equal to the limit then return the tax as income times high rate.
            if (income >= limit)
                taxOwed = Convert.ToInt32(income * highRate);
            return taxOwed;
        }
    }  //end class Rates

    //  Create a class named Taxpayer that has the following data members:
    public class Taxpayer
    {
        //Social Security number (use type string, no dashes between groups).  Use get and set accessors.
        string SSN
        { get; set; }

        int yearlyGrossIncome // Use get and set accessors.
        { get; set; }

        public int taxOwed  //  Use read-only accessor.
        {
            get { return taxOwed; }
        }

        // **  The Taxpayer class should be set up so that its objects are comparable to each other based on tax owed.
        class taxpayer : IComparable
        {
            public int taxOwed { get; set; }
            public int income { get; set; }

            int IComparable.CompareTo(Object o)
            {
                int returnVal;
                taxpayer temp = (taxpayer)o;
                if (this.taxOwed > temp.taxOwed)
                    returnVal = 1;
                else
                    if (this.taxOwed < temp.taxOwed)
                        returnVal = -1;
                    else
                        returnVal = 0;
                return returnVal;


            }  // End IComparable.CompareTo
        } //end taxpayer  IComparable class

        //  **The tax should be calculated whenever the income is set.
        //  The Taxpayer class should have a getRates class method that has the following.
        public static void GetRates()
        {
            //  Local method data members for income limit, low rate and high rate.
            int incomeLimit = 0;
            double lowRate;
            double highRate;
            string userInput;

            //  Prompt the user to enter a selection for either default settings or user input of settings.
            Console.Write("Would you like to enter your own values? (enter 0) or would you like to use the default values? (enter 1):  ");

            /*   If the user selects default the default values you will instantiate a rates object using the default constructor
            * and set the Taxpayer class data member for tax equal to the value returned from calling the rates object CalculateTax method.*/
            userInput = Convert.ToString(Console.ReadLine());

            if (userInput == "1")
            {
                Rates rates = new Rates();
                rates.CalculateTax(incomeLimit);
            } // end if

            /*  If the user selects to enter the rates data then prompt the user to enter values for income limit, low rate and high rate, 
             * instantiate a rates object using the three-argument constructor passing those three entries as the constructor arguments and 
             * set the Taxpayer class data member for tax equal to the valuereturned from calling the rates object CalculateTax method. */

            if (userInput == "0")
            {
                Console.Write("Please enter the income limit: ");
                incomeLimit = Convert.ToInt32(Console.ReadLine());
                Console.Write("Please enter the low rate: ");
                lowRate = Convert.ToDouble(Console.ReadLine());
                Console.Write("Please enter the high rate: ");
                highRate = Convert.ToDouble(Console.ReadLine());

                Rates rates = new Rates(incomeLimit, lowRate, highRate);
                rates.CalculateTax(incomeLimit);

            }  // end if
        }  //end GetRates class



        static void Main(string[] args)
        {
            //  instantiate an array of five (5) Taxpayer objects.

            string SSN = "0";
            int income = 0;
            int tax = 0;
            int x = 1;
            Taxpayer[] taxArray = new Taxpayer[5];


            //  Implement a for-loop that will prompt the user to enter the Social Security Number and gross income.
            for (x = 1; x < taxArray.Length; x++)
            {
                taxArray[x] = new Taxpayer();
                Console.Write("Please enter the Social Security Number for taxpayer {0}:  ", x);
                taxArray[x].SSN = Console.ReadLine();

                //SSN = String.Format("{0:000-00-0000}");
                Console.Write("Please enter the gross income for taxpayer {0}:  ", x);
                taxArray[x].yearlyGrossIncome = Convert.ToInt32(Console.ReadLine());

                Taxpayer.GetRates();

            }  //end for

            //  Implement a for-loop that will display each object as formatted taxpayer SSN, income and calculated tax.
            for (int i = 0; i < 5; i++)
            {

                Console.WriteLine("Taxpayer # {0} SSN: {1}, Income is {2:c}, Tax is {3:c}", i, SSN, income, tax);
            } // end for



            //  Implement a for-loop that will sort the five objects in order by the amount of tax owed and then display 
            //each object as formatted taxpayer SSN, income and calculated tax.

            Array.Sort(taxArray);
            Console.WriteLine("Sorted by tax owed");
            for (int i = 0; x < taxArray.Length; i++)
            {
                Console.WriteLine("Taxpayer # {0} SSN: {1}, Income is {2:c}, Tax is {3:c}", i, SSN, income, tax);


            }


        }  //end main
    } //  end Taxpayer class


}  //end namespace

//  Internal documentation

.

Answer 1

You need to implement IComparable<Taxpayer> on the public class and eliminate the private taxpayer class.

Here is a rewrite of the first part of the Taxpayer class:

public class Taxpayer : IComparable<Taxpayer>
{
    //Social Security number (use type string, no dashes between groups).  Use get and set accessors.
    string SSN
    { get; set; }

    int yearlyGrossIncome // Use get and set accessors.
    { get; set; }

    public int taxOwed  //  Use read-only accessor.
    {
        get { return taxOwed; }
    }

    #region IComparable<Taxpayer> Members

    int IComparable<Taxpayer>.CompareTo(Taxpayer other)
    {
        if (this.taxOwed > other.taxOwed)
            return 1;
        else
            if (this.taxOwed < other.taxOwed)
                return -1;
            else
                return 0;
    }

    #endregion

    //  **The tax should be calculated whenever the income is set.
    //  The Taxpayer class should have a getRates class method that has the following.
    public static void GetRates()

Answer 2

You've already implemented the IComparable interface. I suggest that you use IComparable<taxpayer>.

This is how you could implement IComparable<taxpayer> on the taxpayer class: You don't need to add if statements inside the CompareTo method. Return negative if the value of this is smaller and other is bigger. Return positive if the opposite is true. Return zero if they are equal. That is the case of just subtracting them from each other this.taxOwed - other.taxOwed

class taxpayer : IComparable<taxpayer>
{
    public int taxOwed { get; set; }
    public int income { get; set; }

    public int CompareTo(taxpayer other)
    {
        return taxOwed - other.taxOwed;
    }
} //end taxpayer  IComparable 

If you use it like this:

    public static List<taxpayer> taxPayers = new List<taxpayer>()
    {
        new taxpayer() { income = 1, taxOwed = 1000 },
        new taxpayer() { income = 2, taxOwed = 120 },
        new taxpayer() { income = 3, taxOwed = 7812 },
        new taxpayer() { income = 4, taxOwed = 4210 },
        new taxpayer() { income = 5, taxOwed = 400 },
        new taxpayer() { income = 6, taxOwed = 230 },
    };

    static void Main()
    {
        taxPayers.Sort();

        foreach (var t in taxPayers)
            Console.WriteLine(t.taxOwed);
    }

The output would be:

120
230
400
1000
4210
7812

Update I was confused by the code and I didn't pay attention that there was two classes taxpayer and Taxpayer. Why do you have them both? You only need one and you can implement IComparable<Taxpayer> like above.