Programming C# 3.0, 5th Edition

Variables and Constants

A variable is a storage location within a method. In the preceding examples, both x and y are variables. You can assign values to your variables, and you can change those values programmatically.

You create a variable by declaring its type and then giving it a name. You can initialize the variable with a value when you declare it, and you can assign a new value to that variable at any time, changing the value held in the variable. Example 3-1 illustrates this.

Example 3-1. Initializing and assigning a value to a variable

using System;
using System.Collections.Generic;
using System.Text;




namespace InitializingVariables
{
 class Program
 {
    static void Main(string[] args)
    {


    int myInt = 7;
    System.Console.WriteLine("Initialized, myInt: {0}",
      myInt);


    myInt = 5;
    System.Console.WriteLine("After assignment, myInt: {0}",
      myInt);


    }
 }
}


Output:
Initialized, myInt: 7
After assignment, myInt: 5

Tip

Visual Studio creates a namespace and using directive for every program. To save space, I've omitted these from most of the code examples after this one.

WriteLine( )

The .NET Framework provides a useful method for writing output to the screen. The details of this method, System.Console.WriteLine( ), will become clearer as we progress through the book, but the fundamentals are straightforward. Call the method as shown in Example 3-1, passing in a string that you want printed to the console (the command prompt or shell window) and, optionally, parameters that will be substituted. In the ...