Fundamentals of Debugging

Introduction

So far (in previous lessons), we have learned to debug some values and functions. When it comes to an object, we know that its layout (class, etc) can have fields, properties, and methods. Debuggging can be primarily performed on those members using the same techniques we have already studied.

Practical Learning: Introducing Debugging on an Object

1. Start Microsoft Visual Studio
2. Create a new Console App named StellarWaterPoint10
3. Change the document as follows:

   using static System.Console;
   
   WaterBill bill     = new WaterBill();
   
   bill.InvoiceNumber = 100001;
   
   bill.IdentifyAccount();
   bill.DisplaySummary();
   
   internal enum Classification
   {
       Other,
       Residential,
       GeneralBusiness,
       WaterIntensiveBusiness,
       SocialGovernmentNonProfit,
       UnidentifiedOrUnclassified
   }
   
   internal class WaterBill
   {
       internal int            InvoiceNumber       { get; set; }
       internal double         CounterReadingStart { get; set; }
       internal double         CounterReadingEnd   { get; set; }
       internal Classification Category            { get; set; }
       internal string?        AccountType         { get; set; }
   
       internal string GetAccountType()
       {
           WriteLine("Stellar Water Point");
           WriteLine("==================================================================================");
           WriteLine("To prepare an invoice, enter the following information");
           WriteLine("Types of Accounts");
           WriteLine("1. Residential Household");
           WriteLine("2. General Business");
           WriteLine("3. Social/Government/Non-Profit Organization");
           WriteLine("4. Unidentified or Unclassified Type of Organization");
           WriteLine("5. Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc");
           WriteLine("0. Other");
           Write("Enter Type of Account:       ");
           string acntType = ReadLine()!;
           WriteLine("----------------------------------------------------------------------------------");
   
           return acntType;
       }
   
       internal int ReadCounterStart()
       {
           int value = 0;
           
           try
           {
               Write("Counter Reading Start:       ");
               value = int.Parse(ReadLine()!);
           }
           catch (Exception ex) when (ex is FormatException fex)
           {
               WriteLine("The counter reading start value you entered is not valid.");
               WriteLine("The error produced is: " + fex.Message);
           }
           
           return value;
       }
   
       internal int ReadCounterEnd()
       {
           int value = 0;
           
           try
           {
               Write("Counter Reading End:         ");
               value = int.Parse(ReadLine()!);
           }
           catch (Exception ex) when (ex is FormatException fex)
           {
               WriteLine("The counter reading end value you entered is not valid.");
               WriteLine("The error produced is: " + fex.Message);
           }
           
           return value;
       }
   
       internal void IdentifyAccount()
       {
           string acntType = GetAccountType();
   
           switch (acntType)
           {
               case "1":
                   AccountType = "Residential Household";
                   Category    = Classification.Residential;
                   break;
   
               case "2":
                   AccountType = "General Business";
                   Category    = Classification.GeneralBusiness;
                   break;
   
               case "3":
                   AccountType = "Social/Government/Non-Profit Organization";
                   Category    = Classification.SocialGovernmentNonProfit;
                   break;
   
               case "4":
                   AccountType = "Unidentified or Unclassified Type of Organization";
                   Category    = Classification.UnidentifiedOrUnclassified;
                   break;
   
               case "5":
                   AccountType = "Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc";
                   Category    = Classification.WaterIntensiveBusiness;
                   break;
   
               default:
                   AccountType = "Other";
                   Category    = Classification.Other;
                   break;
           }
   
           CounterReadingStart = ReadCounterStart();
           CounterReadingEnd   = ReadCounterEnd();
       }
   
       internal double Gallons => CounterReadingEnd - CounterReadingStart;
   
       internal double HCFTotal
       {
           // CCF: Centum Cubic Feet
           // HCF: Hundred Cubic Feet
           get
           {
               return Gallons / 748.00;
           }
       }
   
       internal (double First, double Next, double Last) Therms
       {
           get
           {
               double first;
               double next;
               double last;
   
               switch (Category)
               {
                   case Classification.Residential:
                       first = Gallons * 41.50 / 10000.00;
                       next  = Gallons * 32.50 / 10000.00;
                       last  = Gallons * 26.00 / 10000.00;
                       break;
                   case Classification.GeneralBusiness:
                       first = Gallons * 45.00 / 10000.00;
                       next  = Gallons * 30.00 / 10000.00;
                       last  = Gallons * 25.00 / 10000.00;
                       break;
                   case Classification.SocialGovernmentNonProfit:
                       first = Gallons * 46.00 / 10000.00;
                       next  = Gallons * 50.00 / 10000.00;
                       last  = Gallons *  4.00 / 10000.00;
                       break;
                   case Classification.UnidentifiedOrUnclassified:
                       first = Gallons * 25.00 / 10000.00;
                       next  = Gallons * 35.00 / 10000.00;
                       last  = Gallons * 40.00 / 10000.00;
                       break;
                   case Classification.WaterIntensiveBusiness:
                       first = Gallons * 50.00 / 10000.00;
                       next  = Gallons * 40.00 / 10000.00;
                       last  = Gallons * 10.00 / 10000.00;
                       break;
                   default:
                       first = Gallons * (48.00 / 10000.00);
                       next  = Gallons * (32.00 / 10000.00);
                       last  = Gallons * (20.00 / 10000.00);
                       break;
               }
   
               return (first, next, last);
           }
       }
   
       internal double WaterCharges => Therms.First + Therms.Next + Therms.Last;
   
       internal double SewerCharges
       {
           get
           {
               double result = Category switch
               {
                   Classification.Residential                => WaterCharges * 6.826941 / 100,
                   Classification.UnidentifiedOrUnclassified => WaterCharges * 10.6247 / 100,
                   Classification.WaterIntensiveBusiness     => WaterCharges * 12.0535 / 100,
                   Classification.GeneralBusiness            => WaterCharges * 8.3136 / 100,
                   Classification.SocialGovernmentNonProfit  => WaterCharges * 4.162522 / 100,
                   _                                         => WaterCharges * 9.2065 / 100,
               };
   
               return result;
           }
       }
   
       internal double StormCharges
       {
           get
           {
               double result = Category switch
               {
                   Classification.Residential                => WaterCharges * 1.184286 / 100,
                   Classification.UnidentifiedOrUnclassified => WaterCharges * 1.375284 / 100,
                   Classification.WaterIntensiveBusiness     => WaterCharges * 5.606685 / 100,
                   Classification.GeneralBusiness            => WaterCharges * 3.139403 / 100,
                   Classification.SocialGovernmentNonProfit  => WaterCharges * 1.069636 / 100,
                   _                                         => WaterCharges * 0.694748 / 100,
               };
   
               return result;
           }
       }
   
       internal double EnvironmentCharges
       {
           get
           {
               double result = Category switch
               {
                   Classification.Residential                => WaterCharges * .022724,
                   Classification.UnidentifiedOrUnclassified => WaterCharges * .082477,
                   Classification.WaterIntensiveBusiness     => WaterCharges * .413574,
                   Classification.GeneralBusiness            => WaterCharges * .161369,
                   Classification.SocialGovernmentNonProfit  => WaterCharges * 0.118242,
                   _                                         => WaterCharges * 0.221842,
               };
   
               return result;
           }
       }
   
       internal double ServiceCharges
       {
           get => Category switch
           {
               Classification.Residential                => WaterCharges * .145748,
               Classification.UnidentifiedOrUnclassified => WaterCharges * .186692,
               Classification.WaterIntensiveBusiness     => WaterCharges * .412628,
               Classification.GeneralBusiness            => WaterCharges * .242627,
               Classification.SocialGovernmentNonProfit  => WaterCharges * .102246,
               _                                         => WaterCharges * .210248,
           };
       }
   
       internal double TotalCharges
       {
           get
           {
               return WaterCharges + ServiceCharges + StormCharges + EnvironmentCharges + ServiceCharges;
           }
       }
   
       internal double LocalTaxes
       {
           get => Category switch
           {
               Classification.Residential                => TotalCharges * .031574,
               Classification.UnidentifiedOrUnclassified => TotalCharges * .105737,
               Classification.WaterIntensiveBusiness     => TotalCharges * .153248,
               Classification.GeneralBusiness            => TotalCharges * .122517,
               Classification.SocialGovernmentNonProfit  => TotalCharges * .035026,
               _                                         => TotalCharges * .125148,
           };
       }
   
       internal double StateTaxes
       {
           get => Category switch
           {
               Classification.Residential                => TotalCharges * .016724,
               Classification.UnidentifiedOrUnclassified => TotalCharges * .067958,
               Classification.WaterIntensiveBusiness     => TotalCharges * .081622,
               Classification.GeneralBusiness            => TotalCharges * .042448,
               Classification.SocialGovernmentNonProfit  => TotalCharges * .008779,
               _                                         => TotalCharges * .013746,
           };
       }
   
       internal double CalculateAmountDue()
       {
           return TotalCharges + LocalTaxes + StateTaxes;
       }
   
       internal double CalculateLateAmountDue()
       {
           double amt = TotalCharges + LocalTaxes + StateTaxes;
   
           if (Category == Classification.Residential)
           {
               return amt + 8.95;
           }
           else if (Category == Classification.SocialGovernmentNonProfit)
           {
               return amt + (amt / 4.575);
           }
           else if (Category == Classification.GeneralBusiness)
           {
               return amt + (amt / 12.315);
           }
           else if (Category == Classification.UnidentifiedOrUnclassified)
           {
               return amt + (amt / 7.425);
           }
           else if (Category == Classification.WaterIntensiveBusiness)
           {
               return amt + (amt / 15.225);
           }
           else
           {
               return amt + (amt / 6.735);
           }
       }
   
       internal void DisplaySummary()
       {
   
           WriteLine("==================================================================================");
           WriteLine("Stellar Water Point - Customer Invoice");
           WriteLine("----------------------------------------------------------------------------------");
           WriteLine("Water Bill Number:           {0}", InvoiceNumber);
           WriteLine("Account Type:                {0}", AccountType);
           WriteLine("==================================================================================");
           WriteLine("Meter Reading");
           WriteLine("----------------------------------------------------------------------------------");
           WriteLine("Counter Reading Start: {0,10}",   CounterReadingStart);
           WriteLine("Counter Reading End:   {0,10}",   CounterReadingEnd);
           WriteLine("Total Gallons Consumed:{0,10}",   Gallons);
           WriteLine("HCF Total:             {0,10:n}", HCFTotal);
           WriteLine("==================================================================================");
           WriteLine("Therms Evaluation");
           WriteLine("----------------------------------------------------------------------------------");
           WriteLine("First Tier:            {0,10:n}", Therms.First);
           WriteLine("Second Tier:           {0,10:n}", Therms.Next);
           WriteLine("Last Tier:             {0,10:n}", Therms.Last);
           WriteLine("==================================================================================");
           WriteLine("Bill Values");
           WriteLine("----------------------------------------------------------------------------------");
           WriteLine("Water Usage Charges:   {0,10:n}", WaterCharges);
           WriteLine("Sewer Charges:         {0,10:n}", SewerCharges);
           WriteLine("Storm Charges:         {0,10:n}", StormCharges);
           WriteLine("Environment Charges:   {0,10:n}", EnvironmentCharges);
           WriteLine("Service Charges:       {0,10:n}", ServiceCharges);
           WriteLine("Total Charges:         {0,10:n}", TotalCharges);
           WriteLine("----------------------------------------------------------------------------------");
           WriteLine("Local Taxes:           {0,10:n}", LocalTaxes);
           WriteLine("State Taxes:           {0,10:n}", StateTaxes);
           WriteLine("----------------------------------------------------------------------------------");
           WriteLine("Amount Due:            {0,10:n}", CalculateAmountDue());
           WriteLine("Late Amount Due:       {0,10:n}", CalculateLateAmountDue());
           WriteLine("==================================================================================");
       }
   }

Stepping Into an Object

As seen in previous lessons, the primary way to debug an application is to use the Step Into feature. Once you start that, you can use the various tools, namely the windows (Locals, Autos, etc) that assist you while debugging. When it comes to objects, as opposed to variables of primitive types, the windows are equipped to access objects. The members of those objects are also accessed. The values of the properties are displayed. Still, the other techniques we used for variables are available.

Practical Learning: Stepping Into an Object

1. To start debugging, on the main menu, click Debug -> Step Into.
   Move the DOS window so you can see both your code and that window.
   Notice that the debugging focus is on the class instance (WaterBill bill = new WaterBill();)
2. To continue debugging, on the main menu, click Debug and click Step Into.
   Click the Autos tab. Notice the node named bill. Click its right-pointing button to expand it.
   Click the Locals tab. Notice the node named bill. Click its right-pointing button to expand it:

   

Stepping Over a Property

As we know already, the Step Into feature is a good tool to monitor the behavior of variables inside a function. That feature also allows you to know if a function is behaving as expected. In thsame way, you can use the Step Into operation for a property or a property of a class. In some cases, if you have established that a property is behaving as expected, you may want to skip it from debugging. Instead of executing one line at a time, the debugger allows you to execute a whole property at a time or to execute the lines in some properties while skipping the others. To support this, you use a feature named Step Over.

To step over a property, while debugging:

• On the main menu, click Debug -> Step Over
• On the Debug toolbar, click the Step Over button
• Press F10

As its name suggests, the Step Over feature allows you to skip a property if you know it doesn't have any problem. When debugging, you choose what properties to step into and which ones to step over.

Practical Learning: Stepping Over

1. To continue debugging, on the main menu, click Debug and click Step Into.
   A dialog box may display:

   

   If that dialog box comes up, click Yes
2. To continue debugging, on the main menu, click Debug and click Step Into.
   Notice that the debugging focus moves to the begining of the body of the WaterBill.IdentifyAccount() method
3. To continue debugging, on the Debug toolbar, click the Step Into button fifteen times.
   Every time you click, notice the changes in the DOS window
4. When the type of account is requested in the DOS window, type 1 and press Enter
5. To continue debugging, on the Debug toolbar, click the Step Into button five times.
   In the Locals and the Autos window, notice a node named this. Click its right-pointing button to expand it and see the values of the properties
6. To continue debugging, on the main menu, click Debug -> Step Over
7. To stop debugging, on the Debug toolbar, click the Step Out button
8. When the Counter Reading Start value is requested in the DOS window, type 14968 and press Enter
9. When the Counter Reading End value is requested in the DOS window, type 18662 and press Enter.
   In the Autos window, expand the bill node and notice the values of the properties:

   

   Click the Locals tab. Expand the bill node to see the values of the properties:

   

10. To continue debugging, on the Debug toolbar, click the Step Over button twice:

    Stellar Water Point
    ==================================================================================
    To prepare an invoice, enter the following information
    Types of Accounts
    1. Residential Household
    2. General Business
    3. Social/Government/Non-Profit Organization
    4. Unidentified or Unclassified Type of Organization
    5. Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc
    0. Other
    Enter Type of Account:       1
    ----------------------------------------------------------------------------------
    Counter Reading Start:       14968
    Counter Reading End:         18662
    ==================================================================================
    Stellar Water Point - Customer Invoice
    ----------------------------------------------------------------------------------
    Water Bill Number:           100001
    Account Type:                Residential Household
    ==================================================================================
    Meter Reading
    ----------------------------------------------------------------------------------
    Counter Reading Start:      14968
    Counter Reading End:        18662
    Total Gallons Consumed:      3694
    HCF Total:                   4.94
    ==================================================================================
    Therms Evaluation
    ----------------------------------------------------------------------------------
    First Tier:                 15.33
    Second Tier:                12.01
    Last Tier:                   9.60
    ==================================================================================
    Bill Values
    ----------------------------------------------------------------------------------
    Water Usage Charges:        36.94
    Sewer Charges:               2.52
    Storm Charges:               0.44
    Environment Charges:         0.84
    Service Charges:             5.38
    Total Charges:              48.98
    ----------------------------------------------------------------------------------
    Local Taxes:                 1.55
    State Taxes:                 0.82
    ----------------------------------------------------------------------------------
    Amount Due:                 51.35
    Late Amount Due:            60.30
    ==================================================================================
    
    Press any key to close this window . . .

11. In the DOS window, press U to close the window and return to your programming environment
12. Create a new Console App named StellarWaterPoint11
13. To create a new folder, in the Solution Explorer, right-click StellarWaterPoint11 -> Add -> New Folder
14. Type Models as the name of the folder
15. To create a class, in the Solution Explorer, right-click Models -> Add -> Class...
16. Type WaterMeter as the name of the file and class
17. Click Add
18. Change the class as follows:

    namespace StellarWaterPoint11.Models
    {
        internal record WaterMeter
        {
            internal string MeterNumber { get; set; } = string.Empty;
            internal string Make        { get; set; } = string.Empty;
            internal string Model       { get; set; } = string.Empty;
            internal string MeterSize   { get; set; } = string.Empty;
    
            public override string ToString()
            {
                return "Mtr #: " + MeterNumber + " - " +
                       Make      + " "         + Model +
                       "(Meter Size: " + MeterSize + ")";
            }
        }
    }

19. To create a class, in the Solution Explorer, right-click Models -> Add -> Class...
20. Type Classification as the name of the file and class
21. Click Add
22. Change the document as follows:

    namespace StellarWaterPoint11.Models
    {
        internal enum Classification
        {
            Other,
            Residential,
            GeneralBusiness,
            WaterIntensiveBusiness,
            SocialGovernmentNonProfit,
            UnidentifiedOrUnclassified
        }
    }

23. To create a class, in the Solution Explorer, right-click Models -> Add -> Class...
24. Type Customer as the name of the file and class
25. Click Add
26. Change the class as follows:

    namespace StellarWaterPoint11.Models
    {
        internal record class Customer
        {
            internal WaterMeter     Meter         { get; set; }
            internal string         AccountNumber { get; set; } = string.Empty;
            internal string         AccountName   { get; set; } = string.Empty;
            internal string         AccountType   { get; set; } = string.Empty;
            internal string         Address       { get; set; } = string.Empty;
            internal string         City          { get; set; } = string.Empty;
            internal string         County        { get; set; } = string.Empty;
            internal string         State         { get; set; } = string.Empty;
            internal string         ZIPCode       { get; set; } = string.Empty;
            internal Classification Category      { get; set; }
    
            internal Customer()
            {
                Meter = new WaterMeter();
            }
    
            public override string ToString()
            {
                return "Account Number:             " + AccountNumber + Environment.NewLine +
                       "Account Name:               " + AccountName + Environment.NewLine +
                       "Account Type:               " + AccountType + Environment.NewLine +
                       "Address:                    " + Address + Environment.NewLine +
                       "City:                       " + City + Environment.NewLine +
                       "County:                     " + County + Environment.NewLine +
                       "State:                      " + State + Environment.NewLine +
                       "ZIP Code:                   " + ZIPCode;
            }
        }
    }
    

27. To create a class, in the Solution Explorer, right-click Models -> Add -> Class...
28. Type WaterBill as the name of the file and class
29. Click Add
30. Change the document as follows:

    namespace StellarWaterPoint11.Models
    {
        internal record class WaterBill
        {
            internal int       InvoiceNumber       { get; set; } 
            internal Customer? Client              { get; set; }
            internal double    CounterReadingStart { get; set; }
            internal double    CounterReadingEnd   { get; set; }
    
            internal int ReadCounterStart()
            {
                int value = 0;
    
                try
                {
                    Console.Write("Counter Reading Start:       ");
                    value = int.Parse(Console.ReadLine()!);
                }
                catch (Exception ex) when (ex is FormatException fex)
                {
                    Console.WriteLine("The counter reading start value you entered is not valid.");
                    Console.WriteLine("The error produced is: " + fex.Message);
                }
    
                return value;
            }
    
            internal int ReadCounterEnd()
            {
                int value = 0;
    
                try
                {
                    Console.Write("Counter Reading End:         ");
                    value = int.Parse(Console.ReadLine()!);
                }
                catch (Exception ex) when (ex is FormatException fex)
                {
                    Console.WriteLine("The counter reading end value you entered is not valid.");
                    Console.WriteLine("The error produced is: " + fex.Message);
                }
    
                return value;
            }
    
            internal void IdentifyAccount()
            {
                CounterReadingStart = ReadCounterStart();
                CounterReadingEnd   = ReadCounterEnd();
            }
    
            internal double Gallons => CounterReadingEnd - CounterReadingStart;
    
            internal double HCFTotal
            {
                get
                {
                    return Gallons / 748.05;
                }
            }
    
            internal (double First, double Next, double Last) Therms
            {
                get
                {
                    double first;
                    double next;
                    double last;
    
                    switch (Client!.Category)
                    {
                        case Classification.Residential:
                            first = Gallons * 41.50 / 10000.00;
                            next  = Gallons * 32.50 / 10000.00;
                            last  = Gallons * 26.00 / 10000.00;
                            break;
    
                        case Classification.GeneralBusiness:
                            first = Gallons * 45.00 / 10000.00;
                            next  = Gallons * 30.00 / 10000.00;
                            last  = Gallons * 25.00 / 10000.00;
                            break;
    
                        case Classification.SocialGovernmentNonProfit:
                            first = Gallons * 46.00 / 10000.00;
                            next  = Gallons * 50.00 / 10000.00;
                            last  = Gallons *  4.00 / 10000.00;
                            break;
    
                        case Classification.UnidentifiedOrUnclassified:
                            first = Gallons * 25.00 / 10000.00;
                            next  = Gallons * 35.00 / 10000.00;
                            last  = Gallons * 40.00 / 10000.00;
                            break;
    
                        case Classification.WaterIntensiveBusiness:
                            first = Gallons * 50.00 / 10000.00;
                            next  = Gallons * 40.00 / 10000.00;
                            last  = Gallons * 10.00 / 10000.00;
                            break;
    
                        default:
                            first = Gallons * (48.00 / 10000.00);
                            next  = Gallons * (32.00 / 10000.00);
                            last  = Gallons * (20.00 / 10000.00);
                            break;
                    }
    
                    return (first, next, last);
                }
            }
    
            internal double WaterCharges
            {
                get
                {
                    return Therms.First + Therms.Next + Therms.Last;
                }
            }
    
            internal double SewerCharges
            {
                get
                {
                    double result = Client!.Category switch
                    {
                        Classification.Residential                => WaterCharges *  6.826941 / 100.00,
                        Classification.UnidentifiedOrUnclassified => WaterCharges * 10.624729 / 100.00,
                        Classification.WaterIntensiveBusiness     => WaterCharges * 12.053502 / 100.00,
                        Classification.GeneralBusiness            => WaterCharges *  8.313635 / 100.00,
                        Classification.SocialGovernmentNonProfit  => WaterCharges *  4.162522 / 100.00,
                        _                                         => WaterCharges *  9.206253 / 100.00
                    };
    
                    return result;
                }
            }
    
            internal double StormCharges
            {
                get
                {
                    double result = Client!.Category switch
                    {
                        Classification.Residential                => WaterCharges * 1.184286 / 100.00,
                        Classification.UnidentifiedOrUnclassified => WaterCharges * 1.375284 / 100.00,
                        Classification.WaterIntensiveBusiness     => WaterCharges * 5.606685 / 100.00,
                        Classification.GeneralBusiness            => WaterCharges * 3.139403 / 100.00,
                        Classification.SocialGovernmentNonProfit  => WaterCharges * 1.069636 / 100.00,
                        _                                         => WaterCharges *  .694748 / 100.00,
                    };
    
                    return result;
                }
            }
    
            internal double EnvironmentCharges
            {
                get
                {
                    double result = Client!.Category switch
                    {
                        Classification.Residential                => WaterCharges * .022724,
                        Classification.UnidentifiedOrUnclassified => WaterCharges * .082477,
                        Classification.WaterIntensiveBusiness     => WaterCharges * .413574,
                        Classification.GeneralBusiness            => WaterCharges * .161369,
                        Classification.SocialGovernmentNonProfit  => WaterCharges * .118242,
                        _                                         => WaterCharges * .221842
                    };
    
                    return result;
                }
            }
    
            internal double ServiceCharges
            {
                get => Client!.Category switch
                {
                    Classification.Residential                => WaterCharges * .145748,
                    Classification.UnidentifiedOrUnclassified => WaterCharges * .186692,
                    Classification.WaterIntensiveBusiness     => WaterCharges * .412628,
                    Classification.GeneralBusiness            => WaterCharges * .242627,
                    Classification.SocialGovernmentNonProfit  => WaterCharges * .102246,
                    _                                         => WaterCharges * .210248
                };
            }
    
            internal double TotalCharges
            {
                get
                {
                    return WaterCharges + ServiceCharges + StormCharges + EnvironmentCharges + ServiceCharges;
                }
            }
    
            internal double LocalTaxes
            {
                get => Client!.Category switch
                {
                    Classification.Residential                => TotalCharges * .031574,
                    Classification.UnidentifiedOrUnclassified => TotalCharges * .105737,
                    Classification.WaterIntensiveBusiness     => TotalCharges * .153248,
                    Classification.GeneralBusiness            => TotalCharges * .122517,
                    Classification.SocialGovernmentNonProfit  => TotalCharges * .035026,
                    _                                         => TotalCharges * .125148
                };
            }
    
            internal double StateTaxes
            {
                get => Client!.Category switch
                {
                    Classification.Residential                => TotalCharges * .016724,
                    Classification.UnidentifiedOrUnclassified => TotalCharges * .067958,
                    Classification.WaterIntensiveBusiness     => TotalCharges * .081622,
                    Classification.GeneralBusiness            => TotalCharges * .042448,
                    Classification.SocialGovernmentNonProfit  => TotalCharges * .008779,
                    _                                         => TotalCharges * .013746
                };
            }
    
            internal double CalculateAmountDue()
            {
                return TotalCharges + LocalTaxes + StateTaxes;
            }
    
            internal double CalculateLateAmountDue()
            {
                double amt = TotalCharges + LocalTaxes + StateTaxes;
    
                if (Client!.Category == Classification.Residential)
                {
                    return amt + 8.95;
                }
                else if (Client.Category == Classification.SocialGovernmentNonProfit)
                {
                    return amt + (amt / 4.575);
                }
                else if (Client.Category == Classification.GeneralBusiness)
                {
                    return amt + (amt / 12.315);
                }
                else if (Client.Category == Classification.UnidentifiedOrUnclassified)
                {
                    return amt + (amt / 7.425);
                }
                else if (Client.Category == Classification.WaterIntensiveBusiness)
                {
                    return amt + (amt / 15.225);
                }
                else
                {
                    return amt + (amt / 6.735);
                }
            }
    
            internal void DisplaySummary()
            {
                Console.WriteLine("==================================================================================");
                Console.WriteLine("Stellar Water Point - Water Bill Invoice");
                Console.WriteLine("----------------------------------------------------------------------------------");
                Console.WriteLine("Water Bill Number:          {0}", InvoiceNumber);
                Console.WriteLine("==================================================================================");
                Console.WriteLine("Customer Account Information");
                Console.WriteLine("----------------------------------------------------------------------------------");
                Console.WriteLine(Client);
                Console.WriteLine("----------------------------------------------------------------------------------");
                Console.WriteLine("Meter Information:          {0}", Client!.Meter);
                Console.WriteLine("==================================================================================");
                Console.WriteLine("Water Bill Details");
                Console.WriteLine("==================================================================================");
                Console.WriteLine("Meter Reading");
                Console.WriteLine("----------------------------------------------------------------------------------");
                Console.WriteLine("Counter Reading Start:   {0,10}",   CounterReadingStart);
                Console.WriteLine("Counter Reading End:     {0,10}",   CounterReadingEnd);
                Console.WriteLine("Total Gallons Consumed:  {0,10}",   Gallons);
                Console.WriteLine("HCF Total:               {0,10:n}", HCFTotal);
                Console.WriteLine("==================================================================================");
                Console.WriteLine("Therms Evaluation");
                Console.WriteLine("----------------------------------------------------------------------------------");
                Console.WriteLine("First Tier:              {0,10:n}", Therms.First);
                Console.WriteLine("Second Tier:             {0,10:n}", Therms.Next);
                Console.WriteLine("Last Tier:               {0,10:n}", Therms.Last);
                Console.WriteLine("==================================================================================");
                Console.WriteLine("Bill Values");
                Console.WriteLine("----------------------------------------------------------------------------------");
                Console.WriteLine("Water Usage Charges:     {0,10:n}", WaterCharges);
                Console.WriteLine("Sewer Charges:           {0,10:n}", SewerCharges);
                Console.WriteLine("Storm Charges:           {0,10:n}", StormCharges);
                Console.WriteLine("Environment Charges:     {0,10:n}", EnvironmentCharges);
                Console.WriteLine("Service Charges:         {0,10:n}", ServiceCharges);
                Console.WriteLine("Total Charges:           {0,10:n}", TotalCharges);
                Console.WriteLine("----------------------------------------------------------------------------------");
                Console.WriteLine("Local Taxes:             {0,10:n}", LocalTaxes);
                Console.WriteLine("State Taxes:             {0,10:n}", StateTaxes);
                Console.WriteLine("----------------------------------------------------------------------------------");
                Console.WriteLine("Amount Due:              {0,10:n}", CalculateAmountDue());
                Console.WriteLine("Late Amount Due:         {0,10:n}", CalculateLateAmountDue());
                Console.WriteLine("==================================================================================");
            }
        }
    }

31. In the Solution Explorer, right-click Program.cs -> Rename
32. Type BillProcessing (to get BillProcessing.cs) and press Enter
33. Click the BillProcessing.cs tab and change its document as follows:

    using static System.Console;
    using StellarWaterPoint11.Models;
    
    WriteLine("Stellar Water Point");
    WriteLine("=================================================================================");
    WriteLine("To prepare an invoice, enter the following information");
    
    WaterMeter GetWaterMeter()
    {
        var waterMeter = new WaterMeter();
    
        WriteLine("Enter the information about the water meter");
        Write("Meter Number:               ");
        waterMeter.MeterNumber = ReadLine()!;
        Write("Manufacturer:               ");
        waterMeter.Make        = ReadLine()!;
        Write("Model:                      ");
        waterMeter.Model       = ReadLine()!;
        Write("Meter Size:                 ");
        waterMeter.MeterSize   = ReadLine()!;
    
        return waterMeter;
    }
    
    Customer Identity()
    {
        Customer client = new();
    
        WriteLine("=================================================================================");
        WriteLine("Enter the information about the customer");
        WriteLine("---------------------------------------------------------------------------------");
        Write("Account Number:             ");
        client.AccountNumber = ReadLine()!;
        Write("Account Name:               ");
        client.AccountName   = ReadLine()!;
        WriteLine("---------------------------------------------------------------------------------");
        WriteLine("Types of Accounts");
        WriteLine("1. Residential Household");
        WriteLine("2. General Business");
        WriteLine("3. Social/Government/Non-Profit Organization");
        WriteLine("4. Unidentified or Unclassified Type of Organization");
        WriteLine("5. Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc");
        WriteLine("0. Other");
        Write("Enter Type of Account:      ");
        string acntType = ReadLine()!;
    
        switch (acntType)
        {
            case "1":
                client.AccountType = "Residential Household";
                client.Category    = Classification.Residential;
                break;
    
            case "2":
                client.AccountType = "General Business";
                client.Category    = Classification.GeneralBusiness;
                break;
    
            case "3":
                client.AccountType = "Social/Government/Non-Profit Organization";
                client.Category    = Classification.SocialGovernmentNonProfit;
                break;
    
            case "4":
                client.AccountType = "Unidentified or Unclassified Type of Organization";
                client.Category    = Classification.UnidentifiedOrUnclassified;
                break;
    
            case "5":
                client.AccountType = "Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc";
                client.Category    = Classification.WaterIntensiveBusiness;
                break;
    
            default:
                client.AccountType = "Other";
                client.Category    = Classification.Other;
                break;
        }
    
        WriteLine("---------------------------------------------------------------------------------");
        Write("Address:                    ");
        client.Address = ReadLine()!;
        Write("City:                       ");
        client.City    = ReadLine()!;
        Write("County:                     ");
        client.County  = ReadLine()!;
        Write("State:                      ");
        client.State   = ReadLine()!;
        Write("ZIP Code:                   ");
        client.ZIPCode = ReadLine()!;
    
        return client;
    }
    
    WaterBill waterBill     = new WaterBill();
    
    waterBill.InvoiceNumber = 100002;
    
    WaterMeter waterMeter   = GetWaterMeter();
    Customer   customer     = Identity();
    
    customer.Meter          = waterMeter;
    waterBill.Client        = customer;
    
    WriteLine("=================================================================================");
    WriteLine("Water Bill Preparation");
    WriteLine("Enter the water reading information");
    waterBill.IdentifyAccount();
    Clear();
    waterBill.DisplaySummary();

Debugging Objects

Introduction

Just as we learned to debug one object, you can debug an application that contains many classes that lead to various objects. The techniques we used for debugging one object are the same to be applied to many objects. When it comes to objects, you can create their classes in a single file; but in most cases, the classes are created in many files, sometimes each class in its own file. When you debug such an application, the debugger will know how to access each class and its content (methods and properties).

Practical Learning: Examining Local Variables

1. To start debugging, in the Solution Explorer, right-click the name of the project -> Debug -> Step Into New Instance.
   Notice that the debugging focus has moved to the first statement.
   Notice the objects in the Locals window:

   

2. To continue debugging, on the Debug toolbar, click the Step Into button three times.
   Notice that the debugging focus has moved to the first object created (WaterBill waterBill = new WaterBill();)
3. To continue debugging, on the Debug toolbar, click the Step Into button .
   In the Locals window, notice the button on the waterBill node:

   

   Click the right-pointing arrow button to expand the node:

   

   (Don't pay attention to the red icons; we are not concerned with them)
4. To continue debugging, on the Debug toolbar, click the Step Over button
5. To continue debugging, on the Debug toolbar, click the Step Into button three times.
   Notice that the debugging focus has moved to the WaterMeter class in the WaterMeter.cs file.
   In the Locals window, notice the this node. Expand it
6. To continue debugging, on the main menu, click Debug -> Step Into. Do that four times.
   Notice that the debugging focus has returned to the BillProcessing.cs document in the body of the GetWaterMeter() function
7. To continue debugging, on the main menu, click Debug and click Step Into. Do that three times
8. To continue debugging, on the main menu, click Debug and click Step Over
9. When the Meter Number is requested in the DOS window, type 580-742-825 and press Enter
10. To continue debugging, on the main menu, click Debug and click Step Into
11. To continue debugging, on the main menu, click Debug and click Step Over
12. When the Manufacturer value is requested in the DOS window, type Kensa Sons and press Enter
13. To continue debugging, on the main menu, click Debug and click Step Into
14. To continue debugging, press F10 (Step Over)
15. When the value of the Model is requested, type KS2000A and press Enter
16. To continue debugging, on the main menu, click Debug and click Step Into
17. To continue debugging, press F10 (Step Over)
18. When the value of the Meter Size is requested, type 1 3/4 Inches and press Enter
19. To continue debugging, on the Debug toolbar, click the Step Into button .
    Notice the tool tip value on the closing curly bracket of the GetWaterMeter() function.
    In the Locals window, if necessary, expand the waterMeter node:

    

20. To continue debugging, on the Debug toolbar, click the Step Into button twenty-seven times.
    Every time you click, notice the contents of the Locals and the Autos window. Whenever the name of an object appears, expand it and observe the values of the properties
21. To continue debugging, on the main menu, click Debug and click Step Over
22. In the DOS window, when the Account Number is requested, type 4086-938-4783 and press Enter
23. To continue debugging, on the main menu, click Debug and click Step Into
24. To continue debugging, on the main menu, click Debug and click Step Over
25. In the DOS window, when the Account Name is requested, type Bernotte's Doughnuts and press Enter
26. To continue debugging, on the Debug toolbar, click the Step Into button nine times.
    Every time you click, notice the changes in the DOS window, in the Locals and the Autos windows
27. To continue debugging, on the Debug toolbar, click the Step Over button
28. In the DOS window, when the Type of Account is requested, type 4 and press Enter
29. To continue debugging, on the Debug toolbar, click the Step Into button
30. To continue debugging, on the Debug toolbar, click the Step Over button twice
31. To continue debugging, on the Debug toolbar, click the Step Into button four times
32. To continue debugging, on the main menu, click Debug and click Step Over
33. In the DOS window, when the Address is requested, type 10103 Hexagon Drive and press Enter
34. To continue debugging, on the Debug toolbar, click the Step Into button
35. To continue debugging, on the Debug toolbar, click the Step Over button
36. In the DOS window, when the City is requested, type Winterstown and press Enter
37. To continue debugging, on the Debug toolbar, click the Step Into button
38. To continue debugging, on the Debug toolbar, click the Step Over button
39. In the DOS window, when the County is requested, type York and press Enter
40. To continue debugging, on the Debug toolbar, click the Step Into button
41. To continue debugging, on the Debug toolbar, click the Step Over button
42. In the DOS window, when the State is requested, type PA and press Enter
43. To continue debugging, on the Debug toolbar, click the Step Into button
44. To continue debugging, on the Debug toolbar, click the Step Over button
45. In the DOS window, when the ZIP-Code is requested, type 17402-8818 and press Enter
46. To continue debugging, on the Debug toolbar, click the Step Into button .
    Notice the tool tip value on the closing curly bracket of the Identity() function
47. To continue debugging, on the Debug toolbar, click the Step Into button
48. To continue debugging, on the Debug toolbar, click the Step Over button twice
49. To continue debugging, on the Debug toolbar, click the Step Into button ten times
50. In the DOS window, when the Counter Reading Start value is requested, type 11917 and press Enter
51. To continue debugging, on the Debug toolbar, click the Step Into button twice.
    Notice the tool tip value on the closing curly bracket of the ReadCounterStart() function
52. To continue debugging, on the main menu, click Debug and click Step Into
53. To continue debugging, on the Debug toolbar, click the Step Over button twice
54. In the DOS window, when the Counter Reading End is requested, type 11938 and press Enter.
    Notice the tool tip value on the closing curly bracket of the ReadCounterEnd() function
55. To continue debugging, on the Debug toolbar, keep clicking the Step Over button .
    Every time you have clicked, notice the values of the objects and properties in the DOS window, the Locals and the Autos windows.
    Every time you have clicked, position the mouse on various variables in the Code Editor to see their values:

56. To close the DOS window, press P in it and return to your programming environment

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