Taking it out for a test drive in C#

Generator Code-128 in C# Taking it out for a test drive

To convert your C# program into an executable program, choose Build Build ConsoleAppTemplate Visual Studio responds with the following message:

- Build started: Project: ConsoleAppTemplate, Configuration: Debug Any CPU Cscexe /noconfig /nowarn (and much more) Compile complete -- 0 errors, 0 warnings ConsoleAppTemplate -> C:\C#Programs\ (and more)==Build: 1 succeeded or upto-date, 0 failed, 0 skipped==

The key point here is the 1 succeeded part on the last line As a general rule of programming, succeeded is good; failed is bad To execute the program, choose Debug Start Without Debugging The program brings up a black console window and terminates immediately The program has seemingly done nothing In fact, this is the case The template is nothing but an empty shell

Edit the Programcs template file until it appears as follows:

using System; namespace ConsoleAppTemplate { // these are curly braces // class Program is the object containing our code public class Program { // This is where our program starts // Every program has a Main() method somewhere static void Main(string[] args) { // here s our code to make it do something // prompt user to enter a name ConsoleWriteLine( Enter your name, please: ); // now read the name entered string sName = ConsoleReadLine(); // greet the user with the name that was entered ConsoleWriteLine( Hello, + sName); // wait for user to acknowledge the results ConsoleWriteLine( Press Enter to terminate ); ConsoleRead(); // our code in Main() ends here } // Main() ends here } // class Program ends here } // namespace ConsoleAppTemplate ends here

Don t sweat the stuff following the double or triple slashes (// or ///), and don t worry about whether to enter one or two spaces or one or two new lines However, do pay attention to capitalization Choose Build Build ConsoleAppTemplate to convert this new version of Programcs into the ConsoleAppTemplateexe program From within Visual Studio 2005, choose Debug Start Without Debugging The black console window appears and prompts you for your name (You may need to activate the console window by clicking it) Then the window shows Hello, followed by the name entered, and displays Press Enter to terminate Pressing Enter closes the window You can also execute the program from the DOS command line To do so, open a DOS window and enter the following:

Now enter ConsoleAppTemplate to execute the program The output should be identical You can also navigate to the \C#Programs\ConsoleAppTemplate\ bin\Debug folder in Windows Explorer and then double-click the ConsoleAppTemplateexe file To open a DOS window, try choosing Tools Command Window If that command isn t available on your Visual Studio Tools menu, choose Start All Programs Microsoft Visual Studio 2005 Visual Studio Tools Visual Studio 2005 Command Prompt

In the following sections, you take this first C# console app apart one section at a time to understand how it works

The basic framework for all console applications starts with the following code:

using System; using SystemCollectionsGeneric; using SystemText; namespace ConsoleAppTemplate { public class Program { // This is where our 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 brace following Main() I explain the meaning of these statements in due course More than that I cannot say for now The list of using directives can come immediately before or immediately after the phrase namespace HelloWorld { The order doesn t matter You can apply using to lots of things in NET The whole business of namespaces and using is explained in Bonus 2 on the CD