C# Tutorials: Data Reading and Formatting

	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:

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
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, n^th);

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

Practical Learning: Displaying Data With Placeholders

To use curly brackets to display data, change the file as follows:

using System;

namespace GeorgetownCleaningServices3
{
    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("====================================");
	}
    }
}

Execute the program and test it
Close the DOS window

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 Learning: Converting to String

To convert some values to string, change the program as follows:

using System;

namespace GeorgetownCleaningServices3
{
    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("====================================");
	}
    }
}

Execute the program and test it
Close the DOS window

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 Learning: Formatting Data Display

To format data display, change the file as follows:

using System;

namespace GeorgetownCleaningServices3
{
    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           = 5.75M;  // 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("====================================");
	}
    }
}

Execute the application. Here is an example:

-/- Georgetown Cleaning Services -/-
Enter Customer Name:  Gretchen McCormack
Enter Customer Phone: (410) 739-2884
Enter the order date and time (mm/dd/yyyy hh:mm AM/PM)
04/09/2001 10:25 AM
Number of Shirts:  5
Number of Pants:   12
Number of Dresses: 8

The Total order is: 80.951625
Amount Tended? 100

====================================
-/- Georgetown Cleaning Services -/-
====================================
Customer:    Gretchen McCormack
Home Phone:  (410) 739-2884
Date & Time: 4/9/2001 10:25:00 AM
------------------------------------
Item Type  Qty Unit/Price Sub-Total
------------------------------------
Shirts      5     $0.95     $4.75
Pants       12     $2.95     $35.40
Dresses     8     $4.55     $36.40
------------------------------------
Total Order:     $76.55
Tax Rate:        5.75 %
Tax Amount:      $4.40
Net Price:       80.95
------------------------------------
Amount Tended:   $100.00
Difference:      $19.05
====================================

Close the DOS window

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 Learning: Controlling Date/Time Formatting

To control formatting of date and time, change the file as follows:

using System;

namespace GeorgetownCleaningServices3
{
    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("====================================");
	}
    }
}

Execute 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
====================================

Close the DOS window


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