Strings

using System;

class BookClub
{
	static void Main()
	{
		Console.WriteLine("Welcome to the World of C# Programming!");
	}
}

This would produce:

Welcome to the World of C# Programming!

Sometimes, you will need to use a string whose value is not known in advance. Therefore, you can first declare a string variable. To do this, use the string keyword (in fact, it is a class) followed by a name for the variable. The name will follow the rules we defined above. An example of a string declaration is:

string Msg;

After declaring a string, you can give it a primary value by assigning it an empty space, a character, a symbol, a word, or a group of words. The value given to a string must be included in double-quotes. Here are examples of string variables declared and initialized:

string Empty  = "";
string Gender = "F";
string FName  = "Nelson Mandela";
string Msg    = "Welcome to the World of C# Programming! ";

After initializing a string variable, you can use its name in any valid operation or expression. For example, you can display its value on the console using the parentheses of Console.Write() or Console.WriteLine(). Here is an example:

using System;

class BookClub
{
	static void Main()
	{
		string Msg = "Welcome to the World of C# Programming! ";
		Console.WriteLine(Msg);
	}
}

1. To use strings, change the file as follows:
    

   using System; class Program { static void Main() { string customerName; string customerHomePhone; byte shirts; decimal priceOneShirt; byte pants; decimal priceAPairOfPants; ushort otherItems; decimal priceOtherItems; uint orderDay; uint orderMonth; uint orderYear; double mondayDiscount; customerName = "Gregory Almas"; customerHomePhone = "(301) 723-4425"; shirts = 5; priceOneShirt = 0.95M; pants = 2; priceAPairOfPants = 1.95M; otherItems = 3; priceOtherItems = 4.55M; orderDay = 15; orderMonth = 7; orderYear = 2002; mondayDiscount = 0.25; // 25% Console.WriteLine("-/- Georgetown Cleaning Services -/-"); Console.WriteLine("========================"); Console.Write("Customer: "); Console.WriteLine(customerName); Console.Write("Home Phone: "); Console.WriteLine(customerHomePhone); Console.Write("Order Date: "); Console.Write(orderMonth); Console.Write('/'); Console.Write(orderDay); Console.Write('/'); Console.WriteLine(orderYear); Console.WriteLine("------------------------"); Console.WriteLine("Item Type Qty Unit Price"); Console.WriteLine("------------------------"); Console.Write("Shirts "); Console.Write(shirts); Console.Write(" "); Console.WriteLine(priceOneShirt); Console.Write("Pants "); Console.Write(pants); Console.Write(" "); Console.WriteLine(priceAPairOfPants); Console.Write("Other Items "); Console.Write(otherItems); Console.Write(" "); Console.WriteLine(priceOtherItems); Console.WriteLine("------------------------"); Console.Write("Monday Discount: "); Console.Write(mondayDiscount); Console.WriteLine('%'); Console.WriteLine("========================"); Console.WriteLine(); } }

2. Execute the program. This would produce:
    

   -/- Georgetown Cleaning Services -/- ======================== Customer: Gregory Almas Home Phone: (301) 723-4425 Order Date: 7/15/2002 ------------------------ Item Type Qty Unit Price ------------------------ Shirts 5 0.95 Pants 2 1.95 Other Items 3 4.55 ------------------------ Monday Discount: 0.25% ======================== Press any key to continue . . .

3. Close the DOS window

A date is a unit that measures the number of years, months, or days elapsed in a specific period. A time is a unit that counts the number of seconds that have elapsed since midnight of the day considered. Although dates and times are large subjects that would require a detailed study, at this time, we will consider them in simple terms.

To declare a variable that would hold date or time values, use the DateTime data type.

using System;

class NumericRepresentation
{
	static void Main()
	{
		DateTime DateHired;
	}
}

The .NET Framework sets its starting periodic date to January 1, 0001 at midnight (12:00:00 or 0:00 AM). If not assigned a specific value (in future lessons, we will learn that this is equivalent to declaring a variable using the default constructor), the variable is initialized to 1/1/0001 at midnight.

The object data type (it is a class) is used to declare a variable whose type is not primarily defined and can be any of the other data types we have introduced. Here is an example:

using System;

class Exercise
{
	static void Main()
	{
		object Whatever;
	}
}

After creating an object variable, you can use its value as you see fit. For example, you can enter the variable in the parentheses of Console.Write() or Console.WriteLine() to display it in the console window.

1. To start another application, on the main menu, click File -> New Project...
2. In the Templates list, click Console Application and change the Name to RealEstate2
3. Click OK
4. Change the file as follows:
    

   using System; class Program { static void Main() { object PropertyNumber = "293749"; object PropertyType = 'S'; object Stories = 3; object Bedrooms = 4; object Value = 425880; Console.WriteLine("=//= Altair Realty =//="); Console.WriteLine("Properties Inventory"); Console.Write("Property #: "); Console.WriteLine(PropertyNumber); Console.Write("Property Type: "); Console.WriteLine(PropertyType); Console.Write("Stories: "); Console.WriteLine(Stories); Console.Write("Bedrooms: "); Console.WriteLine(Bedrooms); Console.Write("Market Value: "); Console.WriteLine(Value); } }

5. Press Ctrl + F5 to execute the application. This would produce:
    

   =//= Altair Realty =//= Properties Inventory Property #: 293749 Property Type: S Stories: 3 Bedrooms: 4 Market Value: 425880 Press any key to continue . . .

6. Close the DOS window