What is a program? In a practical sense, a Windows program is an executable file that you can run by double-clicking its icon. For example, the version of Microsoft Word that I'm using to write this book is a program. You call that an executable program, or executable for short. The names of executable program files generally end with the extension .exe. Word, for example, is Winword.exe.

But a program is something else, as well. An executable program consists of one or more source files. A C# source file, for instance, is a text file that contains a sequence of C# commands, which fit together according to the laws of C# grammar. This file is known as a source file, probably because it's a source of frustration and anxiety.

Uh, grammar? There's going to be grammar? Just the C# kind, which is much easier than the kind most of us struggled with in junior high school.

The C# programming language is one of those intermediate languages that programmers use to create executable programs. C# combines the range of the powerful but complicated C++ (pronounced "see plus plus") with the ease of use of the friendly but more verbose Visual Basic. (Visual Basic's newer .NET incarnation is almost on par with C# in most respects. As the flagship language of .NET, C# tends to introduce most new features first.) A C# program file carries the extension .cs.

Some wags have pointed out that C-sharp and D-flat are the same note, but you shouldn't refer to this new language as "D-flat" within earshot of Redmond, Washington.

C# is

Finally, C# is an integral part of .NET.

.NET began several years ago as Microsoft's strategy to open up the Web to mere mortals like you and me. Today, it's bigger than that, encompassing everything Microsoft does. In particular, it's the new way to program for Windows. It also gives a C-based language, C#, the simple, visual tools that made Visual Basic so popular.

A little background helps you see the roots of C# and .NET. Internet programming was traditionally very difficult in older languages such as C and C++. Sun Microsystems responded to that problem by creating the Java programming language. To create Java, Sun took the grammar of C++, made it a lot more user-friendly, and centered it around distributed development.

When Microsoft licensed Java some years ago, it ran into legal difficulties with Sun over changes it wanted to make to the language. As a result, Microsoft more or less gave up on Java and started looking for ways to compete with it.

Being forced out of Java was just as well because Java has a serious problem: Although Java is a capable language, you pretty much have to write your entire program in Java to get the full benefit. Microsoft had too many developers and too many millions of lines of existing source code, so Microsoft had to come up with some way to support multiple languages. Enter .NET.

.NET is a framework, in many ways similar to Java's libraries — and the C# language is highly similar to the Java language. Just as Java is both the language itself and its extensive code library, C# is really much more than just the keywords and syntax of the C# language. It's those things empowered by a well-organized library containing thousands of code elements that simplify doing about any kind of programming you can imagine, from Web-based databases to cryptography to the humble Windows dialog box.

Microsoft would claim that .NET is much superior to Sun's suite of Web tools based on Java, but that's not the point. Unlike Java, .NET doesn't require you to rewrite existing programs. A Visual Basic programmer can add just a few lines to make an existing program Web-knowledgeable (meaning that it knows how to get data off the Internet). .NET supports all the common Microsoft languages — and hundreds of other languages written by third-party vendors. However, C# is the flagship language of the .NET fleet. C# is always the first language to access every new feature of .NET.

(You sure ask lots of questions.) The first "Visual" language from Microsoft was Visual Basic. The first popular C-based language from Microsoft was Visual C++. Like Visual Basic, it had Visual in its name because it had a built-in graphical user interface (GUI — pronounced "GOO-ee"). This GUI included everything you needed to develop nifty-gifty C++ programs.

Eventually, Microsoft rolled all its languages into a single environment — Visual Studio. As Visual Studio 6.0 started getting a little long in the tooth, developers anxiously awaited version 7. Shortly before its release, however, Microsoft decided to rename it Visual Studio .NET to highlight this new environment's relationship to .NET.

That sounded like a marketing ploy to me — until I started delving into it. Visual Studio .NET differed quite a bit from its predecessors — enough to warrant a new name. Visual Studio 2010 is the third-generation successor to the original Visual Studio .NET. (Book IV is full of Visual Studio goodness, including instructions for customizing it.)

Okay, that's it. No more questions. (For now, anyway.)

To start Visual Studio, choose Start

Complete these steps to create your C# console app:

The contents of your first console app appear this way:

using ...

namespace Program1
{
  class Program
  {
    static void Main(string[] args)
    {

    }
  }
}

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

Regions help you focus on the code you're working on by hiding code that you aren't. Certain blocks of code — such as the namespace block, class block, methods, and other code items — get a +/− automatically without a #region directive. You can add your own collapsible regions, if you like, by typing #region above a code section and #endregion after it. It helps to supply a name for the region, such as Public methods. This code section looks like this:

#region Public methods
... your code
#endregion Public methods

For now, using System; is the only using directive you really need. You can delete the others; the compiler lets you know whether you're missing one.

To convert your C# program into an executable program, choose Build

- Build started: Project: Program1, Configuration: Debug Any CPU -

Csc.exe /noconfig /nowarn ... (and much more)

Compile complete -- 0 errors, 0 warnings
Program1 -> C:C#Programs ... (and more)==Build: 1 succeeded or up-to-date, 0
    failed, 0 skipped==

The key point here is the 1 succeeded part on the last line.

To execute the program, choose Debug

Tip

An alternative command, Debug

The basic framework for all console applications starts as the following:

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

namespace Program1
{
  public class Program
  {
    // This is where your program starts.
    public static void Main(string[] args)
    {
       // Your code goes here.
    }
  }
}

The program starts executing right after the statement containing Main() and ends at the closed curly brace (}) following Main(). (I explain the meaning of these statements in due course. More than that, I cannot say for now.)

The template already has lots of lines, and I've added several other lines, such as the following (in boldface):

// This is where your program starts.
public static void Main(string[] args)

C# ignores the first line in this example. This line is known as a comment.

Why include lines if the computer ignores them? Because comments explain your C# statements. A program, even in C#, isn't easy to understand. Remember that a programming language is a compromise between what computers understand and what humans understand. These comments are useful while you write the code, and they're especially helpful to the poor sap — possibly you — who tries to re-create your logic a year later. Comments make the job much easier.

The real core of this program is embedded within the block of code marked with Main(), like this:

// Prompt user to enter a name.
Console.WriteLine("Enter your name, please:");

// Now read the name entered.
string name = Console.ReadLine();

// Greet the user with the name that was entered.
Console.WriteLine("Hello, " + name);

The program begins executing with the first C# statement: Console.WriteLine. This command writes the character string Enter your name, please: to the console.

The next statement reads in the user's answer and stores it in a variable (a kind of workbox) named name. (See Chapter 2 of this minibook for more on these storage locations.) The last line combines the string Hello, with the user's name and outputs the result to the console.

The final three lines cause the computer to wait for the user to press Enter before proceeding. These lines ensure that the user has time to read the output before the program continues:

// Wait for user to acknowledge the results.
Console.WriteLine("Press Enter to terminate...");
Console.Read();

This step can be important, depending on how you execute the program and depending on the environment. In particular, running your console app inside Visual Studio, or from Windows Explorer, makes the preceding lines necessary — otherwise, the console window closes so fast you can't read the output. If you open a console window and run the program from there, the window stays open regardless.

The first step is to save those lines in a handy location for future use in a handy place: the Toolbox window. With your Program1 console application open in Visual Studio, follow these steps:

Now that you have your template text stored in the Toolbox, you can reuse it in all console applications you write henceforth. Here's how to use it:

With that boilerplate text in place, you can write the rest of your application above those lines. That's it. You now have a finished console app. Try it out for about 30 seconds. Then you can check out Chapter 2 of this minibook.