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Data Reading and Formatting
 

Data Reading
 

Introduction

In previous lessons, we saw that the Console class allows using the Write() and the WriteLine() functions to display things on the screen. While the Console.Write() method is used to display something on the screen, the Console class provides the Read() method to get a value from the user. To use it, the name of a variable can be assigned to it. The syntax used is:

VariableName = Console.Read();

This simply means that, when the user types something and presses Enter, what the user had typed would be given (the word is assigned) to the variable specified on the left side of the assignment operator.

Read() doesn't always have to assign its value to a variable. For example, it can be used on its own line, which simply means that the user is expected to type something but the value typed by the user would not be used for any significant purpose. For example some versions of C# (even including Microsoft's C# and Borland C#Builder) would display the DOS window briefly and disappear. You can use the Read() function to wait for the user to press any key in order to close the DOS window.

Besides Read(), the Console class also provides the ReadLine() method. Like the WriteLine() member function, after performing its assignment, the ReadLine() method sends the caret to the next line. Otherwise, it plays the same role as the Read() function.

Practical LearningPractical Learning: Introducing Data Reading
  1. Start Microsoft Visual C# or Visual Studio .NET
  2. On the main menu, click File -> New -> Project
  3. If necessary, in the Project Types list of the New Project dialog box, click Visual C# Projects
  4. In the Templates list, click Empty Project
  5. In the Name text box, replace the name with GCS3 and specify the desired path in the Location
  6. Click OK
  7. To create a source file for the project, on the main menu, click Project -> Add New Item...
  8. In the Add New Item dialog box, in the Templates list, click Code File
  9. In the Name text box, delete the suggested name and replace it with Exercise
  10. Click Open
  11. In the empty file, type the following:
      
    using System;

namespace GeorgetownCleaningServices
{
	class OrderProcessing
	{
		static void Main()
		{
			Console.WriteLine();
		}
	}
}
  12. To execute the application, on the main menu, click Debug -> Start Without Debugging
 

String Value Request 

In most assignments of your programs, you will not know the value of a string when writing your application. For example, you may want the user to provide such a string. To request a string (or any of the variables we will see in this lesson), you can call the Console.Read() or the Console.ReadLine() function and assign it to the name of the variable whose value you want to retrieve. Here is an example:

string FirstName;
Console.Write("Enter First Name: ");
FirstName = Console.ReadLine();
  
 

Practical LearningPractical Learning: Reading String Values
  1. To request strings from the user, change the file as follows:
      
    using System;

namespace GeorgetownCleaningServices
{
	class OrderProcessing
	{
		static void Main()
		{
			string CustomerName, HomePhone;

			Console.WriteLine("-/- Georgetown Cleaning Services -/-");
			// Request customer information from the user
			Console.Write("Enter Customer Name:  ");
			CustomerName = Console.ReadLine();
			Console.Write("Enter Customer Phone: ");
			HomePhone = Console.ReadLine();

			Console.WriteLine();
			// Display the receipt
			Console.WriteLine("====================================");
			Console.WriteLine("-/- Georgetown Cleaning Services -/-");
			Console.WriteLine("====================================");
			Console.Write("Customer:   ");
			Console.WriteLine(CustomerName);
			Console.Write("Home Phone: ");
			Console.WriteLine(HomePhone);
			Console.WriteLine("====================================\n");
		}
	}
}
  2. To execute the program, on the main menu, click Debug -> Start Without Debugging. This would produce:
      
    -/- Georgetown Cleaning Services -/-
Enter Customer Name:  James Watson
Enter Customer Phone: (410) 493-2005

====================================
-/- Georgetown Cleaning Services -/-
====================================
Customer:   James Watson
Home Phone: (410) 493-2005
====================================
  3. Return to Visual C#

Number Request

In C#, everything the user types is a string and the compiler would hardly analyze it without your explicit asking it to do so. Therefore, if you want to get a number from the user, first request a string. Here is an example: 

using System;

namespace GeorgetownCleaningServices
{
	class OrderProcessing
	{
		static void Main()
		{
			int Number;
			string strNumber;

			strNumber = Console.ReadLine();
		}
	}
}

After getting the string, you must convert it to a number. To perform this conversion, each data type of the .NET Framework provides a mechanism called Parse. To use Parse(), type the data type, followed by a period, followed by Parse, and followed by parentheses. In the parentheses of Parse, type the string that you requested from the user. Here is an example: 

using System;

namespace GeorgetownCleaningServices
{
	class OrderProcessing
	{
		static void Main()
		{
			int Number;
			string strNumber;

			strNumber = Console.ReadLine();
			Number = int.Parse(strNumber);
		}
	}
}

An advanced but faster way to do this is to type Console.ReadLine() in the parentheses of Parse. This has the same effect. Here is an example: 

using System;

namespace GeorgetownCleaningServices
{
	class OrderProcessing
	{
		static void Main()
		{
			int Number;

			Number = int.Parse(Console.ReadLine());
		}
	}
}

 

Practical LearningPractical Learning: Reading Numeric Values

  1. To retrieve various numbers from the user, change the file as follows:
      
    using System;

namespace GeorgetownCleaningServices
{
	class OrderProcessing
	{
		static void Main()
		{
			// Price of items
			const decimal PriceOneShirt     = 0.95M;
			const decimal PriceAPairOfPants = 2.95M;
			const decimal PriceOneDress     = 4.55M;
			const decimal TaxRate           = 0.0575M;  // 5.75%

			// Customer personal infoirmation
			string CustomerName, HomePhone;
			// Unsigned numbers to represent cleaning items
			uint NumberOfShirts, NumberOfPants, NumberOfDresses;
			// Each of these sub totals will be used for cleaning items
			decimal SubTotalShirts, SubTotalPants, SubTotalDresses;
			// Values used to process an order
			decimal TotalOrder, TaxAmount, SalesTotal;
			decimal AmountTended, Difference;

			Console.WriteLine("-/- Georgetown Cleaning Services -/-");
			// Request customer information from the user
			Console.Write("Enter Customer Name:  ");
			CustomerName = Console.ReadLine();
			Console.Write("Enter Customer Phone: ");
			HomePhone = Console.ReadLine();
			
			// Request the quantity of each category of items
			Console.Write("Number of Shirts:  ");
			string strShirts = Console.ReadLine();
			NumberOfShirts   = uint.Parse(strShirts);
			
			Console.Write("Number of Pants:   ");
			string strPants  = Console.ReadLine();
			NumberOfPants    = uint.Parse(strPants);
			
			Console.Write("Number of Dresses: ");
			string strDresses = Console.ReadLine();
			NumberOfDresses   = uint.Parse(strDresses);
			
			// Perform the necessary calculations
			SubTotalShirts  = NumberOfShirts  * PriceOneShirt;
			SubTotalPants   = NumberOfPants   * PriceAPairOfPants;
			SubTotalDresses = NumberOfDresses * PriceOneDress;
			// Calculate the "temporary" total of the order
			TotalOrder      = SubTotalShirts + SubTotalPants + SubTotalDresses;

			// Calculate the tax amount using a constant rate
			TaxAmount       = TotalOrder * TaxRate;
			// Add the tax amount to the total order
			SalesTotal      = TotalOrder + TaxAmount;

			// Communicate the total to the user...
			Console.Write("\nThe Total order is: ");
			Console.WriteLine(SalesTotal);
			// and request money for the order
			Console.Write("Amount Tended? ");
			AmountTended    = decimal.Parse(Console.ReadLine());

			// Calculate the difference owed to the customer
			// or that the customer still owes to the store
			Difference      = AmountTended - SalesTotal;
			Console.WriteLine();

			// Display the receipt
			Console.WriteLine("====================================");
			Console.WriteLine("-/- Georgetown Cleaning Services -/-");
			Console.WriteLine("====================================");
			Console.Write("Customer:   ");
			Console.WriteLine(CustomerName);
			Console.Write("Home Phone: ");
			Console.WriteLine(HomePhone);
			Console.WriteLine("------------------------------------");
			Console.WriteLine("Item Type  Qty Unit/Price Sub-Total");
			Console.WriteLine("------------------------------------");
			Console.Write("Shirts      ");
			Console.Write(NumberOfShirts);
			Console.Write("     ");
			Console.Write(PriceOneShirt);
			Console.Write("     ");
			Console.WriteLine(SubTotalShirts);
			Console.Write("Pants       ");
			Console.Write(NumberOfPants);
			Console.Write("     ");
			Console.Write(PriceAPairOfPants);
			Console.Write("     ");
			Console.WriteLine(SubTotalPants);
			Console.Write("Dresses     ");
			Console.Write(NumberOfDresses);
			Console.Write("     ");
			Console.Write(PriceOneDress);
			Console.Write("     ");
			Console.WriteLine(SubTotalDresses);
			Console.WriteLine("------------------------------------");
			Console.Write("Total Order:     ");
			Console.WriteLine(TotalOrder);
			Console.Write("Tax Rate:        ");
			Console.Write(TaxRate * 100);
			Console.WriteLine('%');
			Console.Write("Tax Amount:      ");
			Console.WriteLine(TaxAmount);
			Console.Write("Net Price:       ");
			Console.WriteLine(SalesTotal);
			Console.WriteLine("------------------------------------");
			Console.Write("Amount Tended:   ");
			Console.WriteLine(AmountTended);
			Console.Write("Difference:      ");
			Console.WriteLine(Difference);
			Console.WriteLine("====================================");
		}
	}
}
  2. Execute the application. Here is an example of running the program:
     
  3. Return to Visual C#
 

Requesting Dates and Times

As done with the regular numbers, you can request a date value from the user. This is also done by requesting a string from the user. Here is an example:

using System;

namespace ValueRequests
{
	class Exercise
	{
		static void Main()
		{
			string strDateHired;

			strDateHired = Console.ReadLine();
		}
	}
}

After the user has entered the string you can then convert it to a DateTime value. Just like any value you request from the user, a date or time value that the user types must be valid, otherwise, the program would produce an error. Because dates and times follow some rules for their formats, you should strive to let the user know how you expect the value to be entered.

By default, if you request only a date from the user and the user enters a valid date, the compiler would add the midnight value to the date. If you request only the time from the user and the user enters a valid time, the compiler would add the current date to the value. Later on, we will learn how to isolate either only the date or only the time.

Practical LearningPractical Learning: Requesting Date and Time Values
  1. To deal with new dates and times, change the program as follows:
      
    using System;

namespace GeorgetownCleaningServices
{
	class OrderProcessing
	{
		static void Main()
		{
			// Price of items
			const decimal PriceOneShirt     = 0.95M;
			const decimal PriceAPairOfPants = 2.95M;
			const decimal PriceOneDress     = 4.55M;
			const decimal TaxRate           = 0.0575M;  // 5.75%

			// Basic information about an order
			string CustomerName, HomePhone;
			DateTime OrderDate;
			// Unsigned numbers to represent cleaning items
			uint NumberOfShirts, NumberOfPants, NumberOfDresses;
			// Each of these sub totals will be used for cleaning items
			decimal SubTotalShirts, SubTotalPants, SubTotalDresses;
			// Values used to process an order
			decimal TotalOrder, TaxAmount, SalesTotal;
			decimal AmountTended, Difference;

			Console.WriteLine("-/- Georgetown Cleaning Services -/-");
			// Request order information from the user
			Console.Write("Enter Customer Name:  ");
			CustomerName = Console.ReadLine();
			Console.Write("Enter Customer Phone: ");
			HomePhone = Console.ReadLine();
			Console.WriteLine("Enter the order date and time (mm/dd/yyyy hh:mm AM/PM)");
			OrderDate = DateTime.Parse(Console.ReadLine());
			
			// Request the quantity of each category of items
			Console.Write("Number of Shirts:  ");
			string strShirts = Console.ReadLine();
			NumberOfShirts   = uint.Parse(strShirts);
			
			Console.Write("Number of Pants:   ");
			string strPants  = Console.ReadLine();
			NumberOfPants    = uint.Parse(strPants);
			
			Console.Write("Number of Dresses: ");
			string strDresses = Console.ReadLine();
			NumberOfDresses   = uint.Parse(strDresses);
			
			// Perform the necessary calculations
			SubTotalShirts  = NumberOfShirts  * PriceOneShirt;
			SubTotalPants   = NumberOfPants   * PriceAPairOfPants;
			SubTotalDresses = NumberOfDresses * PriceOneDress;
			// Calculate the "temporary" total of the order
			TotalOrder      = SubTotalShirts + SubTotalPants + SubTotalDresses;

			// Calculate the tax amount using a constant rate
			TaxAmount       = TotalOrder * TaxRate;
			// Add the tax amount to the total order
			SalesTotal      = TotalOrder + TaxAmount;

			// Communicate the total to the user...
			Console.Write("\nThe Total order is: ");
			Console.WriteLine(SalesTotal);
			// and request money for the order
			Console.Write("Amount Tended? ");
			AmountTended    = decimal.Parse(Console.ReadLine());

			// Calculate the difference owed to the customer
			// or that the customer still owes to the store
			Difference      = AmountTended - SalesTotal;
			Console.WriteLine();

			// Display the receipt
			Console.WriteLine("====================================");
			Console.WriteLine("-/- Georgetown Cleaning Services -/-");
			Console.WriteLine("====================================");
			Console.Write("Customer:    ");
			Console.WriteLine(CustomerName);
			Console.Write("Home Phone:  ");
			Console.WriteLine(HomePhone);
			Console.Write("Date & Time: ");
			Console.WriteLine(OrderDate);
			Console.WriteLine("------------------------------------");
			Console.WriteLine("Item Type  Qty Unit/Price Sub-Total");
			Console.WriteLine("------------------------------------");
			Console.Write("Shirts      ");
			Console.Write(NumberOfShirts);
			Console.Write("     ");
			Console.Write(PriceOneShirt);
			Console.Write("     ");
			Console.WriteLine(SubTotalShirts);
			Console.Write("Pants       ");
			Console.Write(NumberOfPants);
			Console.Write("     ");
			Console.Write(PriceAPairOfPants);
			Console.Write("     ");
			Console.WriteLine(SubTotalPants);
			Console.Write("Dresses     ");
			Console.Write(NumberOfDresses);
			Console.Write("     ");
			Console.Write(PriceOneDress);
			Console.Write("     ");
			Console.WriteLine(SubTotalDresses);
			Console.WriteLine("------------------------------------");
			Console.Write("Total Order:     ");
			Console.WriteLine(TotalOrder);
			Console.Write("Tax Rate:        ");
			Console.Write(TaxRate * 100);
			Console.WriteLine('%');
			Console.Write("Tax Amount:      ");
			Console.WriteLine(TaxAmount);
			Console.Write("Net Price:       ");
			Console.WriteLine(SalesTotal);
			Console.WriteLine("------------------------------------");
			Console.Write("Amount Tended:   ");
			Console.WriteLine(AmountTended);
			Console.Write("Difference:      ");
			Console.WriteLine(Difference);
			Console.WriteLine("====================================");
		}
	}
}
  2. Execute the application. Here is an example of running the program:
      
    -/- Georgetown Cleaning Services -/-
Enter Customer Name:  Alexander Pappas
Enter Customer Phone: (301) 397-9764
Enter the order date and time (mm/dd/yyyy hh:mm AM/PM)
06/22/98 08:26 AM
Number of Shirts:  2
Number of Pants:   6
Number of Dresses: 0

The Total order is: 20.727000
Amount Tended? 50

====================================
-/- Georgetown Cleaning Services -/-
====================================
Customer:    Alexander Pappas
Home Phone:  (301) 397-9764
Date & Time: 6/22/1998 8:26:00 AM
------------------------------------
Item Type  Qty Unit/Price Sub-Total
------------------------------------
Shirts      2     0.95     1.90
Pants       6     2.95     17.70
Dresses     0     4.55     0
------------------------------------
Total Order:     19.60
Tax Rate:        5.7500%
Tax Amount:      1.127000
Net Price:       20.727000
------------------------------------
Amount Tended:   50
Difference:      29.273000
====================================
  3. Return to Visual C#

Formatting Data Display
 

Introduction

Instead of using two Write() or a combination of Write() and WriteLine() to display data, you can convert a value to a string and display it directly. To do this, you can provide two strings to the Write() or WriteLine() and separate them with a comma:

  1. The first part of the string provided to Write() or WriteLine() is the complete string that would display to the user. This first string itself can be made of different sections:
    1. One section is a string in any way you want it to display
    2. Another section is a number included between an opening curly bracket "{" and a closing curly bracket "}". This combination of "{" and "}" is referred to as a placeholder

      You can put the placeholder anywhere inside of the string. The first placeholder must have number 0. The second must have number 1, etc. With this technique, you can create the string anyway you like and use the placeholders anywhere inside of the string
  2. The second part of the string provided to Write() or WriteLine() is the value that you want to display. It can be one value if you used only one placeholder with 0 in the first string. If you used different placeholders, you can then provide a different value for each one of them in this second part, separating the values with a comma

Here are examples:

using System;

// An Exercise class
class Exercise
{ 
    static void Main()
    {
	String FullName = "Anselme Bogos";
         int Age = 15;
         double HSalary = 22.74;

         Console.WriteLine("Full Name: {0}", FullName);
         Console.WriteLine("Age: {0}", Age);
         Console.WriteLine("Distance: {0}", HSalary);
 
         Console.WriteLine();
    }
}

This would produce:

Full Name: Anselme Bogos
Age: 15
Distance: 22.74

As mentioned already, the numeric value typed in the curly brackets of the first part is an ordered number. If you want to display more than one value, provide each incremental value in its curly brackets. The syntax used is:

Write("To Display {0} {1} {2} {n}", First, Second, Third, nth);

You can use the sections between a closing curly bracket and an opening curly bracket to create a meaningful sentence.

 

Practical LearningPractical Learning: Displaying Data With Placeholders
  1. To use curly brackets to display data, change the file as follows:
      
    using System;

namespace GeorgetownCleaningServices
{
	class OrderProcessing
	{
		static void Main()
		{
			// Price of items
			const decimal PriceOneShirt     = 0.95M;
			const decimal PriceAPairOfPants = 2.95M;
			const decimal PriceOneDress     = 4.55M;
			const decimal TaxRate           = 0.0575M;  // 5.75%

			// Basic information about an order
			string CustomerName, HomePhone;
			DateTime OrderDate;
			// Unsigned numbers to represent cleaning items
			uint NumberOfShirts, NumberOfPants, NumberOfDresses;
			// Each of these sub totals will be used for cleaning items
			decimal SubTotalShirts, SubTotalPants, SubTotalDresses;
			// Values used to process an order
			decimal TotalOrder, TaxAmount, SalesTotal;
			decimal AmountTended, Difference;

			Console.WriteLine("-/- Georgetown Cleaning Services -/-");
			// Request order information from the user
			Console.Write("Enter Customer Name:  ");
			CustomerName = Console.ReadLine();
			Console.Write("Enter Customer Phone: ");
			HomePhone = Console.ReadLine();
	Console.WriteLine("Enter the order date and time (mm/dd/yyyy hh:mm AM/PM)");
			OrderDate = DateTime.Parse(Console.ReadLine());
			
			// Request the quantity of each category of items
			Console.Write("Number of Shirts:  ");
			NumberOfShirts = uint.Parse(Console.ReadLine());
			
			Console.Write("Number of Pants:   ");
			NumberOfPants = uint.Parse(Console.ReadLine());
			
			Console.Write("Number of Dresses: ");
			NumberOfDresses = uint.Parse(Console.ReadLine());
			
			// Perform the necessary calculations
			SubTotalShirts  = NumberOfShirts  * PriceOneShirt;
			SubTotalPants   = NumberOfPants   * PriceAPairOfPants;
			SubTotalDresses = NumberOfDresses * PriceOneDress;
			// Calculate the "temporary" total of the order
			TotalOrder      = SubTotalShirts + SubTotalPants + SubTotalDresses;

			// Calculate the tax amount using a constant rate
			TaxAmount       = TotalOrder * TaxRate;
			// Add the tax amount to the total order
			SalesTotal      = TotalOrder + TaxAmount;

			// Communicate the total to the user...
			Console.Write("\nThe Total order is: ");
			Console.WriteLine(SalesTotal);
			// and request money for the order
			Console.Write("Amount Tended? ");
			AmountTended    = decimal.Parse(Console.ReadLine());

			// Calculate the difference owed to the customer
			// or that the customer still owes to the store
			Difference      = AmountTended - SalesTotal;
			Console.WriteLine();

			// Display the receipt
			Console.WriteLine("====================================");
			Console.WriteLine("-/- Georgetown Cleaning Services -/-");
			Console.WriteLine("====================================");
			Console.WriteLine("Customer:    {0}", CustomerName);
			Console.WriteLine("Home Phone:  {0}", HomePhone);
			Console.WriteLine("Date & Time: {0}", OrderDate);
			Console.WriteLine("------------------------------------");
			Console.WriteLine("Item Type  Qty Unit/Price Sub-Total");
			Console.WriteLine("------------------------------------");
			Console.WriteLine("Shirts      {0}     {1}     {2}",
					NumberOfShirts, PriceOneShirt, SubTotalShirts);
			Console.WriteLine("Pants       {0}     {1}     {2}",
					NumberOfPants, PriceAPairOfPants, SubTotalPants);
			Console.WriteLine("Dresses     {0}     {1}     {2}",
				          NumberOfDresses, PriceOneDress, SubTotalDresses);
			Console.WriteLine("------------------------------------");
			Console.WriteLine("Total Order:     {0}", TotalOrder);
			Console.WriteLine("Tax Rate:        {0}%", TaxRate * 100);
			Console.WriteLine("Tax Amount:      {0}", TaxAmount);
			Console.WriteLine("Net Price:       {0}", SalesTotal);
			Console.WriteLine("------------------------------------");
			Console.WriteLine("Amount Tended:   {0}", AmountTended);
			Console.WriteLine("Difference:      {0}", Difference);
			Console.WriteLine("====================================");
		}
	}
}
  2. Execute the program and run it. Here is an example:
     
  3. Return to Visual C#

Conversion To String

We mentioned earlier that everything the user types using the keyboard is primarily a string and it's your job to convert it to the appropriate type. In reverse, if you have a value that is not a string, you can easily convert it to a string. To support this, each .NET Framework data type provides a mechanism called ToString. Normally, in C#, as we mentioned with boxing, and as we have done so far, this conversion is automatically or transparently done by the compiler. In some cases, you will need to perform the conversion yourself.

To conversion a value of a primitive data type to a string, type the name of the variable, followed by a period, followed, followed by ToString(). Here is an example:

 
using System;

// An Exercise class
class Exercise
{ 
	static void Main()
	{
		String FullName = "Anselme Bogos";
		int Age = 15;
		double HSalary = 22.74;

		Console.WriteLine("Full Name: {0}", FullName);
		Console.WriteLine("Age: {0}", Age.ToString());
		Console.WriteLine("Distance: {0}", HSalary.ToString());
 
		Console.WriteLine();
	}
}

In some cases, you will type something in the parentheses of ToString().

Practical LearningPractical Learning: Converting to String
  1. To convert some values to string, change the program as follows:
      
    using System;

namespace GeorgetownCleaningServices
{
	class OrderProcessing
	{
		static void Main()
		{
			// Price of items
			const decimal PriceOneShirt     = 0.95M;
			const decimal PriceAPairOfPants = 2.95M;
			const decimal PriceOneDress     = 4.55M;
			const decimal TaxRate           = 0.0575M;  // 5.75%


			. . . No Change

			Console.WriteLine("------------------------------------");
			Console.WriteLine("Shirts      {0}     {1}     {2}",
					NumberOfShirts.ToString(), PriceOneShirt,
					SubTotalShirts.ToString());
			Console.WriteLine("Pants       {0}     {1}     {2}",
					NumberOfPants, PriceAPairOfPants, SubTotalPants);
			Console.WriteLine("Dresses     {0}     {1}     {2}",
				          NumberOfDresses, PriceOneDress, SubTotalDresses);
			Console.WriteLine("------------------------------------");
			Console.WriteLine("Total Order:     {0}", TotalOrder);
			Console.WriteLine("Tax Rate:        {0}%", TaxRate * 100);
			Console.WriteLine("Tax Amount:      {0}", TaxAmount.ToString());
			Console.WriteLine("Net Price:       {0}", SalesTotal);
			Console.WriteLine("------------------------------------");
			Console.WriteLine("Amount Tended:   {0}", AmountTended);
			Console.WriteLine("Difference:      {0}", Difference);
			Console.WriteLine("====================================");
		}
	}
}
  2. Execute the program
  3. After testing it, return to Visual C#

Number Formatting

To properly display data in a friendly and most familiar way, you can format it. Formatting tells the compiler what kind of data you are using and how you want the compiler to display it to the user. As it happens, you can display a natural number in a common value or, depending on the circumstance, you may prefer to show it as a hexadecimal value. When it comes to double-precision numbers, you may want to display a distance with three values on the right side of the decimal separator and in some cases, you may want to display a salary with only 2 decimal places.

The System namespace provides a specific letter that you can use in the Write() or WriteLine()'s placeholder for each category of data to display. To format a value, in the placeholder of the variable or value, after the number, type a colon and one of the appropriate letter from the following table. If you are using ToString(), then, in the parentheses of ToString(), you can include a specific letter or combination inside of double-quotes. The letters and their meanings are:

  Character Used For
  c C Currency values
  d D Decimal numbers
  e E Scientific numeric display such as 1.45e5
  f F Fixed decimal numbers
  g G General and most common type of numbers
  n N Natural numbers
  r R Roundtrip formatting
  x X Hexadecimal formatting
  p P Percentages

Here are examples:

using System;

// An Exercise class
class Exercise
{    
    static void Main()
    {
        double Distance = 248.38782;
        int Age = 15;
        int NewColor = 3478;
        double HSalary = 22.74, HoursWorked = 35.5018473;
        double WeeklySalary = HSalary * HoursWorked;

        Console.WriteLine("Distance: {0}", Distance.ToString("E"));
        Console.WriteLine("Age: {0}", Age.ToString());
        Console.WriteLine("Color: {0}", NewColor.ToString("X"));
        Console.WriteLine("Weekly Salary: {0} for {1} hours",
                           WeeklySalary.ToString("c"), HoursWorked.ToString("F"));
     
        Console.WriteLine();
    }
}

This would produce:

Distance: 2.483878E+002
Age: 15
Color: D96
Weekly Salary: $807.31 for 35.50 hours

As you may have noticed, if you leave the parentheses of ToString() empty, the compiler would use a default formatting to display the value.

As opposed to calling ToString(), you can use the above letters in the curly brackets of the first part of Write() or WriteLine(). In this case, after the number in the curly brackets, type the colon operator followed by the letter.

 

Practical LearningPractical Learning: Formatting Data Display
  1. To format data display, change the file as follows:
      
    using System;

namespace GeorgetownCleaningServices
{
	class OrderProcessing
	{
		static void Main()
		{
			// Price of items
			const decimal PriceOneShirt     = 0.95M;
			const decimal PriceAPairOfPants = 2.95M;
			const decimal PriceOneDress     = 4.55M;
			const decimal TaxRate           = 0.575M;  // 5.75%

			// Basic information about an order
			string CustomerName, HomePhone;
			DateTime OrderDate;
			// Unsigned numbers to represent cleaning items
			uint NumberOfShirts, NumberOfPants, NumberOfDresses;
			// Each of these sub totals will be used for cleaning items
			decimal SubTotalShirts, SubTotalPants, SubTotalDresses;
			// Values used to process an order
			decimal TotalOrder, TaxAmount, SalesTotal;
			decimal AmountTended, Difference;

			Console.WriteLine("-/- Georgetown Cleaning Services -/-");
			// Request order information from the user
			Console.Write("Enter Customer Name:  ");
			CustomerName = Console.ReadLine();
			Console.Write("Enter Customer Phone: ");
			HomePhone = Console.ReadLine();
	Console.WriteLine("Enter the order date and time (mm/dd/yyyy hh:mm AM/PM)");
			OrderDate = DateTime.Parse(Console.ReadLine());
			
			// Request the quantity of each category of items
			Console.Write("Number of Shirts:  ");
			NumberOfShirts = uint.Parse(Console.ReadLine());
			
			Console.Write("Number of Pants:   ");
			NumberOfPants = uint.Parse(Console.ReadLine());
			
			Console.Write("Number of Dresses: ");
			NumberOfDresses = uint.Parse(Console.ReadLine());
			
			// Perform the necessary calculations
			SubTotalShirts  = NumberOfShirts  * PriceOneShirt;
			SubTotalPants   = NumberOfPants   * PriceAPairOfPants;
			SubTotalDresses = NumberOfDresses * PriceOneDress;
			// Calculate the "temporary" total of the order
			TotalOrder      = SubTotalShirts + SubTotalPants + SubTotalDresses;

			// Calculate the tax amount using a constant rate
			TaxAmount       = TotalOrder * TaxRate;
			// Add the tax amount to the total order
			SalesTotal      = TotalOrder + TaxAmount;

			// Communicate the total to the user...
			Console.Write("\nThe Total order is: ");
			Console.WriteLine(SalesTotal);
			// and request money for the order
			Console.Write("Amount Tended? ");
			AmountTended    = decimal.Parse(Console.ReadLine());

			// Calculate the difference owed to the customer
			// or that the customer still owes to the store
			Difference      = AmountTended - SalesTotal;
			Console.WriteLine();

			// Display the receipt
			Console.WriteLine("====================================");
			Console.WriteLine("-/- Georgetown Cleaning Services -/-");
			Console.WriteLine("====================================");
			Console.WriteLine("Customer:    {0}", CustomerName);
			Console.WriteLine("Home Phone:  {0}", HomePhone);
			Console.WriteLine("Date & Time: {0}", OrderDate);
			Console.WriteLine("------------------------------------");
			Console.WriteLine("Item Type  Qty Unit/Price Sub-Total");
			Console.WriteLine("------------------------------------");
			Console.WriteLine("Shirts      {0}     {1:C}     {2}",
					NumberOfShirts.ToString(), PriceOneShirt,
					SubTotalShirts.ToString("C"));
			Console.WriteLine("Pants       {0}     {1:C}     {2:C}",
					NumberOfPants, PriceAPairOfPants,
					SubTotalPants);
			Console.WriteLine("Dresses     {0}     {1:C}     {2:C}",
				          NumberOfDresses, PriceOneDress, SubTotalDresses);
			Console.WriteLine("------------------------------------");
			Console.WriteLine("Total Order:     {0:C}", TotalOrder);
			Console.WriteLine("Tax Rate:        {0:P}", TaxRate);
			Console.WriteLine("Tax Amount:      {0}", TaxAmount.ToString("C"));
			Console.WriteLine("Net Price:       {0:F}", SalesTotal);
			Console.WriteLine("------------------------------------");
			Console.WriteLine("Amount Tended:   {0:C}", AmountTended);
			Console.WriteLine("Difference:      {0:C}", Difference);
			Console.WriteLine("====================================");
		}
	}
}
  2. Execute the application. Here is an example:
     
  3. Return to Visual C#

Line Formatting

In the above programs, to display a line of text, we easily used Write() or WriteLine(). To position text of different lengths one above the other, we had to "corrupt" a string by including extra-empty spaces. Such a technique is uncertain and less professional. Fortunately, you can highly format how a string or a line of text should display. The .NET Framework provides mechanisms to control the amount of space used to display a string of text and how to align that string on its line.

To specify the amount of space used to display a string, you can use its placeholder in Write() or WriteLine(). To do this, in the placeholder, type the 0 or the incrementing number of the placer and its formatting character if necessary and if any. Then, type a comma followed by the number of characters equivalent to the desired width. Here are examples:

using System;

// An Exercise class
class Exercise
{ 
	static void Main()
	{
		String FullName = "Anselme Bogos";
		int Age = 15;
		double HSalary = 22.74;

		Console.WriteLine("Full Name: {0,20}", FullName);
		Console.WriteLine("Age:{0,14}", Age.ToString());
		Console.WriteLine("Distance: {0:C,8}", HSalary.ToString());
 
		Console.WriteLine();
	}
}

This would produce:

Full Name:        Anselme Bogos
Age:            15
Distance: 22.74

The sign you provide for the width is very important. If it is positive, the line of text is aligned to the right. This should be your preferred alignment for numeric values. If the number is negative, then the text is aligned to the left.

Data and Time Formatting

As mentioned earlier, when the user enters a date value for a DateTime variable, the compiler adds a time part to the value. Fortunately, if you want to consider only the date or only the time part, you can specify this to the compiler. To support this, the DateTime data type provides a series of letters you can use to format how its value should be displayed to the user. The character is entered in the placeholder of the DateTime variable after the 0 or the incremental numeric value.

Practical LearningPractical Learning: Controlling Date/Time Formatting
  1. To control formatting of date and time, change the file as follows:
      
    using System;

namespace GeorgetownCleaningServices
{
	class OrderProcessing
	{
		static void Main()
		{
			// Price of items
			const decimal PriceOneShirt     = 0.95M;
			const decimal PriceAPairOfPants = 2.95M;
			const decimal PriceOneDress     = 4.55M;
			const decimal TaxRate           = 0.0575M;  // 5.75%

			// Basic information about an order
			string CustomerName, HomePhone;
			DateTime OrderDate, OrderTime;
			// Unsigned numbers to represent cleaning items
			uint NumberOfShirts, NumberOfPants, NumberOfDresses;
			// Each of these sub totals will be used for cleaning items
			decimal SubTotalShirts, SubTotalPants, SubTotalDresses;
			// Values used to process an order
			decimal TotalOrder, TaxAmount, SalesTotal;
			decimal AmountTended, Difference;

			Console.WriteLine("-/- Georgetown Cleaning Services -/-");
			// Request order information from the user
			Console.Write("Enter Customer Name:  ");
			CustomerName = Console.ReadLine();
			Console.Write("Enter Customer Phone: ");
			HomePhone = Console.ReadLine();
			Console.Write("Enter the order date(mm/dd/yyyy):  ");
			OrderDate = DateTime.Parse(Console.ReadLine());
			Console.Write("Enter the order time(hh:mm AM/PM): ");
			OrderTime = DateTime.Parse(Console.ReadLine());

			// Request the quantity of each category of items
			Console.Write("Number of Shirts:  ");
			NumberOfShirts = uint.Parse(Console.ReadLine());
			
			Console.Write("Number of Pants:   ");
			NumberOfPants = uint.Parse(Console.ReadLine());
			
			Console.Write("Number of Dresses: ");
			NumberOfDresses = uint.Parse(Console.ReadLine());
			
			// Perform the necessary calculations
			SubTotalShirts  = NumberOfShirts  * PriceOneShirt;
			SubTotalPants   = NumberOfPants   * PriceAPairOfPants;
			SubTotalDresses = NumberOfDresses * PriceOneDress;
			// Calculate the "temporary" total of the order
			TotalOrder      = SubTotalShirts + SubTotalPants + SubTotalDresses;

			// Calculate the tax amount using a constant rate
			TaxAmount       = TotalOrder * TaxRate;
			// Add the tax amount to the total order
			SalesTotal      = TotalOrder + TaxAmount;

			// Communicate the total to the user...
			Console.WriteLine("\nThe Total order is: {0:C}", SalesTotal);
			// and request money for the order
			Console.Write("Amount Tended? ");
			AmountTended    = decimal.Parse(Console.ReadLine());

			// Calculate the difference owed to the customer
			// or that the customer still owes to the store
			Difference      = AmountTended - SalesTotal;
			Console.WriteLine();

			// Display the receipt
			Console.WriteLine("====================================");
			Console.WriteLine("-/- Georgetown Cleaning Services -/-");
			Console.WriteLine("====================================");
			Console.WriteLine("Customer:    {0}", CustomerName);
			Console.WriteLine("Home Phone:  {0}", HomePhone);
			Console.WriteLine("Order Date:  {0:D}", OrderDate);
			Console.WriteLine("Order Time:  {0:t}", OrderTime);
			Console.WriteLine("------------------------------------");
			Console.WriteLine("Item Type  Qty Unit/Price Sub-Total");
			Console.WriteLine("------------------------------------");
			Console.WriteLine("Shirts     {0}   {1}       {2}",
					NumberOfShirts.ToString(),
				         PriceOneShirt.ToString("C"),
				         SubTotalShirts.ToString("C"));
			Console.WriteLine("Pants      {0}   {1}        {2}",
					NumberOfPants.ToString(),
				         PriceAPairOfPants.ToString("C"),
					SubTotalPants.ToString("C"));
			Console.WriteLine("Dresses    {0}   {1}        {2}",
				         NumberOfDresses.ToString(),
				         PriceOneDress.ToString("C"),
				         SubTotalDresses.ToString("C"));
			Console.WriteLine("------------------------------------");
		Console.WriteLine("Total Order:   {0}", TotalOrder.ToString("C"));
		Console.WriteLine("Tax Rate:      {0}", TaxRate.ToString("P"));
		Console.WriteLine("Tax Amount:    {0}", TaxAmount.ToString("C"));
		Console.WriteLine("Net Price:     {0}", SalesTotal.ToString("C"));
		Console.WriteLine("------------------------------------");
		Console.WriteLine("Amount Tended: {0}", AmountTended.ToString("C"));
		Console.WriteLine("Difference:    {0}", Difference.ToString("C"));
		Console.WriteLine("====================================");
		}
	}
}
  2. Save, compile, and run the program. Here is an example:
      
    -/- Georgetown Cleaning Services -/-
Enter Customer Name:  Antoinette Calhoun
Enter Customer Phone: (703) 797-1135
Enter the order date(mm/dd/yyyy):  04/12/2002
Enter the order time(hh:mm AM/PM): 2:12 PM
Number of Shirts:  5
Number of Pants:   2
Number of Dresses: 1

The Total order is: $16.07
Amount Tended? 20

====================================
-/- Georgetown Cleaning Services -/-
====================================
Customer:    Antoinette Calhoun
Home Phone:  (703) 797-1135
Order Date:  Friday, April 12, 2002
Order Time:  2:12 PM
------------------------------------
Item Type  Qty Unit/Price Sub-Total
------------------------------------
Shirts     5   $0.95       $4.75
Pants      2   $2.95        $5.90
Dresses    1   $4.55        $4.55
------------------------------------
Total Order:   $15.20
Tax Rate:      5.75 %
Tax Amount:    $0.87
Net Price:     $16.07
------------------------------------
Amount Tended: $20.00
Difference:    $3.93
====================================
  3. Type Exit and close Notepad
 
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