2. Lecture 2 - Learning C# Basics
• Introducing the .NET Platform.
• Steps involved in C# program development.
• Computer Programming Languages.
• What Is .NET?
• Writing a Simple C# Program.
• Commenting Code.
• Identifiers and Keywords.
• Convention and Style.
• Getting Started with C# and Visual Studio 2008.
3. How user interacts with Computer
• Click to edit Master text styles
App
lica
– Second level Soft tion
ware
– Third level
• Fourth level
– Fifth level
http://www.nickhalstead.com/wp-content/computer-user.jpg
5. Why Computer Programs?
A computer program is a sequence of instructions that enable a computer to accomplish a particular task.
6. Computer Programming Languages
A programming language is a machine-readable artificial language
designed to express computations that can be performed by a
machine, particularly a computer.
Programming languages can be used to create
programs that specify the behavior of a machine,
to express algorithms precisely, or as a mode of human communication.
http://en.wikipedia.org/wiki/Programming_language
• http://www.levenez.com/lang/
• http://www.engin.umd.umich.edu/CIS/course.des/cis400/
7. How you can select a Computer
Programming Language
How you can select a Computer Programming Language
8. What Is .NET?
• Microsoft .NET, is a platform for developing
software.
• You are building applications on: Microsoft .NET
(pronounced “Dot Net”).
• You learn about the parts of .NET,
– including the Common Language Runtime (CLR),
– the .NET Framework Class Library, and how .NET supports
multiple languages.
9. NET supports multiple programming
languages.
• Literally dozens of languages target the .NET CLR as a platform.
PF I
PF II ITA
10. What Can a C# Program Do?
• Typical programming tasks includes putting data
into a database or pulling it out, displaying high
speed graphics in a game or video, controlling
electronic devices attached to the PC or even
playing music and/or sound effects.
• You can even write software to generate music
or help you compose.
http://cplus.about.com/od/introductiontoprogramming/a/cshbeginners.htm
11. Is C# The Best Programming
Language?
• Some computer languages were written for a specific
purpose.
– Java was originally devised to control toasters.
– C for Operating Systems Programming.
– Pascal to teach good programming techniques.
• But C# is a general purpose language with features to make
programs more robust.
– Fully OOP
– Automatic garbage collection (don’t have to delete objects)
– No pointers
– Only booleans allowed in if statements
– Everything inherits from System.Object
– Array bounds checking at runtime
12. Which Computers Can Run C#?
Any that can run the
• .NET framework.
• On Linux under MonoProject & IDE.
13. How Do I Get Started With C#?
• .NET framework.
• First you need a Editor.
• Then a C# compiler.
– There are a number of commercial and free ones available.
– The list below has instructions for downloading and installing two free compilers.
– Both are completely free and include an IDE to make life easier for you to edit, compile and debug your
applications.
– Download and Install Borland's Turbo C# Explorer.
– Download and Install Microsoft's Visual C# 2005 Express Edition.
14. Could I Get A Programming Job?
• There are an increasing number of C# jobs out there and
it has the backing of Microsoft so is likely to be around
for a considerable length of time.
• The top three most popular programming languages
according to the quarterly Tiobe.com survey, are Java, C
and C#.
• Eg. Search Google
– “most popular programming languages”
– “C# + Salary”
15. How to write Computer Programs
• There are four general phases
– Specify the problem,
– Analyze and break down into a series of steps towards
solution, (i.e., design an algorithm),
– Write the code,
– Compile and run (i.e., test the program)
18. Where Do I Go Now?
• First you have to learn to program in C#.
– Text Book
– MSDN
– Internet
– E-books
– Join The Forums
– http://dotnetforum.lk/
– Etc.
19. Writing a Simple C# Program
Editor / IDE Project Type
Notepad Console Application
Visual Studio 2008 Windows Forms
Application
20. C# - Console Applications
using Visual Studio 2008 Command Prompt
• Step I
– Open a notepad.
• Step II
– Write the following code and save as “FirstProgram.cs”.
• Step III
– Open Visual Studio 2008 Command Prompt.
– Change the current directory to the place where you save “FirstProgram.cs”.
• Step IV
– Type “csc FirstProgram1.cs” compile command.
• Step IV
– Run FirstProgram1.exe
22. Demo One
• How to create a C# console application using
Visual Studio 2008 Command Prompt.
23. C# - Windows Applications
using Visual Studio 2008
• Step I
• Run Microsoft Visual studio 2008.
• Step II
• Create new project “Windows Forms Application”
• Step III
• Design Interface / Form
• Step IV
• Compile
• Step V
• Run
24. Demo Two
• How to create a C# Windows Forms
application using Visual Studio 2008.
– Solution
– Project
• .EXE
25. Demo Three
Navigating through Design and Code modes.
Different windows / Features in VS2008 IDE.
26. C# - Convention and Style
• It is common practice in C# to use whitespace and indentation to facilitate easier reading of code.
• The names should describe what the program does.
• A program may have any amount of white-space between language elements.
• Identifiers are structured, using either Pascal casing or camel casing.
• In Pascal casing the first letter of each word in a name is capitalized
– HelloWorld, DotProduct, and AmortizationSchedule.
– This is normally used in all instances except for parameters (passed to methods), private fields (class member
variables), and local variables (method variables).
• With camel casing, the first letter of the first word is lowercase, and subsequent words are capitalized.
– bookTitle, employeeName, and totalCompensation.
– Parameters, private fields, and local variables use camel casing.
27. Commenting Code
• Part of writing good code is ensuring it is properly documented.
• These commenting techniques prove useful any time you want to comment out a block of incomplete code to get a good compile or
any other time you want to leave a block of code in place temporarily.
• The compiler ignores comments when reading the source code.
• There are three types of commenting syntax in C#:
– single line
– multiline
– XML
• The multiline and single-line comments are great for helping yourself or other programmers understand your code.
• XML documentation commenting feature that is good for both reading code and providing external documentation .
28. • Single-Line Comments
– They begin with the double forward slash marker,
//The single-line comment
• Multiline Comments
– Multiline comment delimiters are the begin comment /* and end comment */ markers.
– Anything between these two markers is considered a comment.
/*
* File Name: Program.cs
* Author: Nishani Ranpatabendi
*/
• XML Documentation Comments
– XML documentation comment supports tools that extract comments into an external XML document.
– This XML can be consumed by tools or run through XSLT style sheets to produce readable documentation.
– XML documentation comments start with a triple slash, ///, on each line.
– /// <summary>
– /// first method executed in application
– /// </summary>
– /// <param name=”args”>command-line options</param>
– static void Main(string[] args)
– {
– // other code
– }
29. Identifiers and Keywords
• Identifiers and keywords are important because you need to know
how to name your variables, custom types, methods, and so on.
• Identifiers are names of the types and variables in your program.
• Keywords are reserved words in the C# language.
• The difference between identifiers and keywords is that keywords
are reserved for C# language syntax and can’t be used for naming
your variables, types, and so on.
30. Reserved words in the C# language
You can prefix keywords with the @ character and use it as an identifier.
31. Case Sensitive Languages
• C# programming language is case sensitive.
– If the language considers two identifiers to be different if
they consist of the same characters in the same order except
for variations in upper and lower case.
• Name name NAME would be three different
identifiers in a language which is case sensitive.
• C# is case sensitive.
32. Summery
• Introducing the .NET Platform.
• Steps involved in C# program development.
• Computer Programming Languages.
• What Is .NET?
• Writing a Simple C# Program.
• Commenting Code.
• Identifiers and Keywords.
• Convention and Style.
• Getting Started with C# and Visual Studio 2008.
33. Reference
http://msdn.microsoft.com/en-us/vcsharp/bb798022.aspx
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Notes de l'éditeur
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Software/ computer programs for different purposes We have Microsoft office package