Hello World in Visual C#

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    • #1874
      msaqib
      Participant

      Here is how Hello World looks in Visual C#:

      Listing 1. Hello World in Visual C# (HelloCS.cs)

      This code is a little longer than the equivalent for Managed Extensions for C++. The syntax for accessing the core library is new; it specifies the namespace rather than the name of the file in which it is found:

      using System;
      The most striking difference is the class specification:

      class MainApp {
      In Visual C#, all code must be contained in methods of a class. So, to house the entry-point code, you must first create a class. (The name of the class does not matter here). Next, you specify the entry point itself:

      public static void Main () {
      The compiler requires this to be called Main. The entry point must also be marked with both public and static. In addition, as with the Managed Extensions for C++ example, the entry point takes no arguments and does not return anything (although different signatures for more sophisticated programs are certainly possible).

      The next line is:

      Console.WriteLine(“Hello World using C#!”);      
      Again, this line writes a string using the runtime Console type. In Visual C#, however, you are able to use a period (.) to indicate the scope. Also, you do not have to place an L before the string because, in C#, all strings are Unicode.

      The Build.bat file contains the single line that is necessary to build this program:

      csc.exe /debug+ /out:.HelloCS.exe helloCS.cs
      In this admittedly simple case, you do not have to specify anything other than the file to compile. In particular, C# does not use the additional step of linking that is required by C++:

      C:…HelloWorldcs>build
      C:…HelloWorldcs>csc.exe /debug+ /out:.HelloCS.exe hellocs.cs
      Microsoft (R) Visual C# Compiler Version …[CLR version…]
      Copyright (C) Microsoft Corp 2000-2001. All rights reserved.
      The default output of the C# compiler is an executable file of the same name, and running this program generates the following output:

      C:…HelloWorldcs>hellocs
      Hello World using Visual C#!

    • #3128
      Anonymous
      Inactive

      Can I know what is “HELLO WORLD” for?

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