Introduction to C

1
Introduction to C

• What is C
• C Programming
• Comparison among C, C and Java

2
Why C

• Competitive threats need shorter cycle time and
  incremental version for a program.
  
• Embrace emerging web programming standards, like
  HTML, XML and SOAP.
  
• Combination of the power of C and VBs high
  productivity and ease of use
  

3
Why C

• C Microsoft answer to Java
• The lawsuit (settled in late 2001)
• Microsoft was forced to drop Java license for
  future development
  
• Microsoft retains its right to distribute its
  current products for seven years
  
• Microsoft cannot update their current products
  without passing Suns compatibility tests beyond
  bug fixes

4
C Features

• As a .NET programming language
• -.NET, designed by Microsoft, is a new framework
  to accomplish many programming tasks.
  
• -.NET is a set of Microsoft software technologies
  for connecting information, people, systems and
  devices. It enables an unprecedented level of
  software integration through the use of XML web
  services.

5
Basic Elements of .NET

• Microsoft .NET platform provides a suite of
  developer tools, client applications, XML web
  services, and servers necessary to participate in
  the connected world

6
C Features (cond)

• As an Object Oriented Language
• -C is not language interoperable, you need
  access to the header files from the original
  source code in order to be able to inherit
  classes.
• -C provides real cross-language code reuse using
  true object-oriented principles, your classes can
  be inherited from and used by other .NET-aware
  code without requiring access to your source
  files.

7
C Features (Cond)

• As an Intermediate Level Programming Language
• -Level of language available to Windows
  developer
  
•   Lowest Assembly Language        
  C, C             C, J        
          VB Highest         VBA,
  scripting languages
• Note Higher level, easier to learn and quicker
  to develop, but less efficient code.

8
C Features (Cond)

• As an Intermediate Level Programming Language
• -fill a perceived gap between VB and C.
• -C has a syntax that is very similar to C, and
  supports many C language features.
  
• -C mostly takes the VB path on memory management
  - the language itself takes responsibility for
  handling it.
  

9
A Simple C Program

• // Namespace Declarationusing System//
  Program start classclass WelcomeCSS    //
  Main begins program execution.    public static
  void Main()            // Write to
  console        Console.WriteLine("Welcome to the
  C Station Tutorial!")    

10
Four Primary Elements in C Program

• I A Namespace Declaration
• -Namespaces contain groups of code that can be
  called upon by C programs.  With the "using
  System" declaration, you are telling your
  program that it can reference the code in the
  "System" namespace without pre-pending the word
  "System" to every reference.

11
Four Primary Elements in C Program (Cond)

• II A Class Declaration
• -Contains the data and method definitions that
  your program uses to execute.
  
• -This particular class "class WelcomeCSS" has no
  data, but it does have one method.  This method
  defines the behavior of this class
  
• III. Main Method
• -Reserved for the starting point of a program.

12
Four Primary Elements in C Program (Cond)

• IV A Program Statement
• -"Console" is a class in the "System" namespace.
• -"WriteLine(...)" is a method in the "Console"
  class.
  
• -We could also write this statement as
  "System.Console.WriteLine(...)".
  
• The program can be compiled with the following
  command line csc Welcome.cs. This produces a
  file named Welcome.exe, which can then be
  executed.

13
C vs. Java

• I. Similarities
• -a single rooted class hierarchy, where all
  classes in C are subclasses of System.Object the
  same way all Java classes are subclasses of
  java.lang.Object.
• -Virtual Machines and Language Runtimes. Just
  like Java is typically compiled to Java byte code
  which then runs in managed execution environment
  (the Java Virtual Machine or JVM), so also is C
  code compiled to an Intermediate Language (IL)
  which then runs in the Common Language Runtime
  (CLR).

14
C vs. Java (Cond)

• I. Similarities
• -Similar Keywords

15
C vs. Java (Cond)

• I. Similarities
• -No Global Methods Just like Java and unlike
  C, methods in C have to be part of a class
  either as member or static methods.
  
• -Interface C, like Java, supports the concept
  of an interface which is akin to a pure abstract
  class. Similarly C and Java both allow only
  single inheritance of classes but multiple
  implementations of interfaces.
• -Array Declaration

16
C vs. Java (Cond)

• I. Similarities
• -Main method In C, it is Main, but in Java,
  it is lower case main. It is typically
  recommended that one creates a main method for
  each class in an application to test the
  functionality of that class besides whatever main
  method actually drives the application.

17
C vs. Java (Cond)

• II. Differences
• -Inheritance Syntax C uses C syntax for
  inheritance, both for class inheritance and
  interface implementation, while Java uses the
  extends and implements keywords.
• C Code Java Code
• using System class B extends A
  implements Comparable
  
• class BA, IComparable

18
C vs. Java (Cond)

• II. Differences
• -Namespaces A C namespace is a way to group a
  collection of classes and is used in a manner
  similar to Java's package construct.
  
• -Constructors, destructors The syntax and
  semantics for constructors in C is identical to
  that in Java. C also has the concept of
  destructors which use syntax similar to C
  destructor syntax but have the mostly the same
  semantics as Java finalizers.

19
C vs. Java (Cond)

• II. Differences
• -Assess Modifier

20
C vs. Java (Cond)

• II. Differences
• -Declare constant
• C const int i10
• Java final int i10
• -Nested classes C has the equivalent of Java's
  static nested classes but has nothing analogous
  to Java's inner classes.

21
C vs. Java (Cond)

• II. Differences
• -Collections A number of popular programming
  languages contain a collections framework which
  typically consists of a number of data structures
  for holding multiple objects as well as
  algorithms for manipulating the objects within
  the aforementioned data structures. The C
  collections framework consists of the classes in
  the System.Collections namespace. The Java
  collections framework consists of a large number
  of the classes and interfaces in the java.util
  package.

22
C vs. Java (Cond)

• II. Differences
• -goto unlike Java, C contains the goto
  statement which can be used to jump directly from
  a point in the code to a label. goto can be
  used in certain situations to reduce code
  duplication while enhancing readability.
• -interoperability C have better backward
  compatibility with C or C code than Java

23
C vs. C

• C is Cs closest relative. C statements are
  quite similar to C statements. C builds on the
  syntax and semantics of C, allowing C
  programmers to take advantage of .NET and the
  common language runtime.
• C is a low-level platform-neutral
  object-oriented programming language. C is a
  somewhat higher-level component-oriented
  language. With the managed environment of .NET,
  C give up that level of control. While .NET
  framework is available to any .NET language, C
  is a language that's well-designed for
  programming with the framework's rich set of
  classes, interfaces, and objects.

24
C vs. C (Cond)

• C code does not require header files. All code
  is written inline.
  
• the use of pointers in C is much less important
  than in C. Pointers can be used in C, where
  the code is marked as 'unsafe', but they are only
  really useful in situations where performance
  gains are at an absolute premium.
• C distinguishes between value types and
  reference types. Simple types (int, long, double,
  and so on) and structs are value types, while all
  classes are reference types, as are Objects.

25
C vs. C (Cond)

• Properties
• Most C programmers try to keep member variables
  private. This data hiding promotes encapsulation
  and allows developers to change implementation of
  the class without breaking the interface the
  clients rely on.
• In C, properties are first-class members of
  classes. To the client, a property looks like a
  member variable, but to the implementor of the
  class it looks like a method. This arrangement
  allows the total encapsulation and data hiding
  while giving developer clients easy access to the
  members.

26
C vs. C (Cond)

• Arrays
• C provides an array class which is a smarter
  version of the traditional C/C array. For
  example, it is not possible to write past the
  bounds of a C array. In addition, Array has an
  even smarter cousin, ArrayList, which can grow
  dynamically to manage the changing size
  requirements of your program.
• Arrays in C come in three flavors
  single-dimensional, multidimensional rectangular
  arrays (like the C multidimensional arrays),
  and jagged arrays (arrays of arrays).

27
References

• http//msdn.microsoft.com/vstudio/techinfo/article
  s/upgrade/Csharpintro.asp
  
• http//www.csharp-station.com/Tutorials/Lesson01.a
  spx
  
• http//www.simonrobinson.com/IntroCSh.htm
• http//216.239.39.100/search?qcacheJmxDra9zDjcC
  www.25hoursaday.com/CsharpVsJava.htmlC23hlzh-C
  NieUTF-8
  
• http//www.microsoft.com/net/basics/
• http//genamics.com/developer/csharp_comparative.h
  tm
  
• http//www.softsteel.co.uk/tutorials/cSharp/lesson
  2.html
  
• http//msdn.microsoft.com/msdnmag/issues/01/07/cto
  csharp/default.aspx