中文XML论坛--C#快餐

贴子主题： C#快餐－1

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发信人: walts (休息一会), 信区: DotNET
标  题: C#快餐－1
发信站: BBS 水木清华站 (Thu Jul 26 01:00:50 2001)

Lesson 1. Hello World

   The simplest C# program is, of course, HelloWorld. You will need C#
compiler, which comes as a part of .Net Framework Beta2 SDK. In your favorite
text editor enter the following code:
class hello
//This program does not do much
{
    static public void Main()
    {
       System.Console.WriteLine("Hello World");
    }
}
Save this file as myhello.cs and type
csc myhello.cs
If you haven't made any typos, something like:
Microsoft (R) Visual C# Compiler Version 7.00.9030
[CLR version 1.00.2204.21]

Copyright (C) Microsoft Corp 2000. All rights reserved.
will appear in your command prompt window. The C# compiler have created
an executable code as a binary file in the PE format named myhello.exe.
By simply typing myhello you will see

Hello World

What does this simple C# program look like? Java! Note that all methods end
with semicolons and Main() method is a part of class Hello. Statements are
enclosed in braces. Like in Java and C/C++,  every program has a Main() entry
point. However in Java the name of the program should be the same as the
name of the class. There is no such restriction in C#. System.Console is a
namespace that takes care of console I/O  (see exercise 5). Other methods of
System.Console include Write method which does not add carriage return at the
end of the line and ReadLine which gets user input from the console.

Exercises
1. Write a routine that asks a user some questions and gives meaningful
output based on her answers.
2.  Use your VC++ 6.0 compiler (not VC++ 7.0 that comes with Beta SDK) to
compile  the following program:
#include<iostream>
//This program does not do much
{
    void main()
    {
       cout<<"Hello World";
    }
}
Now, type dumbin /all myhello.exe >myhello.txt and dumbin /all myhelloC.exe
to dump  contents of myhello.exe and myhelloC.exe. Are executables  myhello.
exe and myhelloC.exe  in the same binary format? Do you think myhelloC.exe
would run on a computer which does not have .Net Framework installed.?
3. Rewrite the HelloWorld program in VB.Net
4. Rewrite the HelloWorld program in Managed C++
5. I have mentioned that System.Console class takes care of Console I/O and
error streams. Explore other classes in System namespace.
6. Find a mistake in this page.
7. Write a really cool program and send it to me. Do not forget to put a lot
of comments.

--

A great poem is a fountain forever overflowing with the
　waters of wisdom and delight.
　　　　　　　　　　　
                                          —— Shelley

※ 来源:·BBS 水木清华站 smth.org·[FROM: 166.111.142.118]
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