public static void Main()
    {
        Employee jack = new Employee();

        jack.Hours = 186;
        jack.Rate  = 52;

        SalesPerson jill = new SalesPerson(186, 52, 64000);

        Console.WriteLine("Jack's ID is {0}, Income is {1:0.00} and Tax is {2:0.00}", jack.Id, jack.GetIncome(), GetIncomeTax(jack));
        Console.WriteLine("Jill's ID is {0}, Income is {1:0.00} and Tax is {2:0.00}", jill.Id, jill.GetIncome(), GetIncomeTax(jill));

        Console.WriteLine("Number of Employees = {0}", Employee.CountInstances());
    }
    public static void Main()
    {
        Employee jack = new Employee();

        jack.Hours = 186;
        jack.Rate  = 52;

        SalesPerson jill = new SalesPerson(186, 52, 48000);

        Console.WriteLine("Jack's ID is {0}, Income is {1:0.00} and Tax is {2:0.00}", jack.Id, jack.GetIncome(), jack.GetIncomeTax());         //Program.GetIncomeTax(jack)
        Console.WriteLine("Jill's ID is {0}, Income is {1:0.00} and Tax is {2:0.00}", jill.Id, jill.GetIncome(), jill.GetIncomeTax());
    }