1. C# Programming: From Problem Analysis to Program Design
Your First C#
Program 2
C# Programming: From Problem Analysis to Program Design
C# Programming: From Problem Analysis to Program Design

2. Chapter Objectives
Distinguish between the different types of applications that can be created with C#
Explore a program written in C#
Examine the basic elements of a C# program
Learn about installing the .NET Framework
C# Programming: From Problem Analysis to Program Design

3. Chapter Objectives (continued)
Compile, run, and build an application
Debug an application
Create an application that displays output
Work through a programming example that illustrates the chapter’s concepts
C# Programming: From Problem Analysis to Program Design

4. Types of Applications Developed with C#
Web applications
Windows graphical user interface (GUI) applications
Console-based applications
Class libraries and stand-alone components (.dlls), smart device applications, and services can also be created
C# Programming: From Problem Analysis to Program Design

5. Web Applications
C# was designed with the Internet applications in mind
Can quickly build applications that run on the Web with C#
Using Web Forms: part of ASP.NET
C# Programming: From Problem Analysis to Program Design

6. Web Applications (continued)
Figure 2-1 Web application written using C#
C# Programming: From Problem Analysis to Program Design

7. Windows Applications Applications designed for the desktop
Designed for a single platform
Use classes from System.Windows.Form
Applications can include menus, pictures, drop- down controls, buttons, textboxes, and labels
Use drag-and-drop feature of Visual Studio
C# Programming: From Problem Analysis to Program Design

8. Windows Applications (continued)
Figure 2-2 Windows application written using C#
C# Programming: From Problem Analysis to Program Design

9. Console Applications Normally send requests to the operating system
Display text on the command console
Easiest to create
Simplest approach to learning software development
Minimal overhead for input and output of data
C# Programming: From Problem Analysis to Program Design

10. Exploring the First C# Program
line // This is traditionally the first program written.
line using System;
line namespace FirstProgram
line {
line class HelloWorld
line {
line static void Main( )
line {
line Console.WriteLine(“Hello World!”);
line }
line }
line }
Comments in green
Keywords in blue
C# Programming: From Problem Analysis to Program Design

11. Output from the First C# Program
Console-based application output
Figure 2-3 Output from Example 2-1 console application
C# Programming: From Problem Analysis to Program Design

12. Elements of a C# Program
Comments
line 1 // This is traditionally the first program written.
Like making a note to yourself or readers of your program
Not considered instructions to the computer
Not checked for rule violations
Document what the program statements are doing
C# Programming: From Problem Analysis to Program Design

13. Comments Make the code more readable Three types of commenting syntax
Inline comments
Multiline comments
XML documentation comments
C# Programming: From Problem Analysis to Program Design

14. Inline Comments Indicated by two forward slashes (//)
Considered a one-line comment
Everything to the right of the slashes ignored by the compiler
Carriage return (Enter) ends the comment
// This is traditionally the first program written.
C# Programming: From Problem Analysis to Program Design

15. Multiline Comment
Forward slash followed by an asterisk (/*) marks the beginning
Opposite pattern (*/) marks the end
Also called block comments
/* This is the beginning of a block multiline comment. It can go on for several lines or just be on a single line. No additional symbols are needed after the beginning two characters. Notice there is no space placed between the two characters. To end the comment, use the following symbols. */
C# Programming: From Problem Analysis to Program Design

16. XML Documentation Comments
Extensible Markup Language (XML)
Markup language that provides a format for describing data using tags
Similar to HTML tags
Three forward slashes (///) mark beginning of comment
Advanced documentation technique used for XML-style comments
Compiler generates XML documentation from them
C# Programming: From Problem Analysis to Program Design

17. using Directive
Permits use of classes found in specific namespaces without having to qualify them
Framework class library
Over 2,000 classes included
Syntax
using namespaceIdentifier;
C# Programming: From Problem Analysis to Program Design

18. namespace
Namespaces provide scope for the names defined within the group
Captain example
Groups semantically related types under a single umbrella
System: most important and frequently used namespace
Can define your own namespace
Each namespace enclosed in curly braces: { }
C# Programming: From Problem Analysis to Program Design

19. namespace (continued)
Predefined namespace (System)– part of .NET FCL
From Example 2-1
line // This is traditionally the first program written.
line using System;
line namespace FirstProgram
line {
line }
User defined namespace
Body of user defined namespace
C# Programming: From Problem Analysis to Program Design

20. class Building block of object-oriented program
Everything in C# is designed around a class
Every program must have at least one class
Classes define a category, or type, of object
Every class is named
C# Programming: From Problem Analysis to Program Design

21. class (continued)
line // This is traditionally the first program written.
line using System;
line namespace FirstProgram
line {
line class HelloWorld
line {
line }
line }
User defined class
C# Programming: From Problem Analysis to Program Design

22. class (continued) Define class members within curly braces
Include data members
Stores values associated with the state of the class
Include method members
Performs some behavior of the class
Can call predefined classes’ methods
Main( )
C# Programming: From Problem Analysis to Program Design

23. Main( ) “Entry point” for all applications
Where the program begins execution
Execution ends after last statement in Main( )
Can be placed anywhere inside the class definition
Applications must have one Main( ) method
Begins with uppercase character
C# Programming: From Problem Analysis to Program Design

24. Main( ) Method Heading line 7 static void Main( )
Begins with the keyword static
Second keyword → return type
void signifies no value returned
Name of the method
Main is the name of Main( ) method
Parentheses “( )” used for arguments
No arguments for Main( ) – empty parentheses 
C# Programming: From Problem Analysis to Program Design

25. Body of a Method Enclosed in curly braces Includes program statements
Example Main( ) method body
line static void Main( )
line {
line Console.WriteLine(“Hello World!”);
line }
Includes program statements
Calls to other method
Here Main( ) calling WriteLine( ) method
C# Programming: From Problem Analysis to Program Design

26. Method Calls Program statements
line Console.WriteLine(“Hello World!”);
Program statements
WriteLine( ) → member of the Console class
Main( ) invoking WriteLine( ) method
Member of Console class
Method call ends in semicolon
C# Programming: From Problem Analysis to Program Design

27. Program Statements Write ( ) → Member of Console class
Argument(s) enclosed in double quotes inside ( )
“Hello World!” is the method’s argument
“Hello World!” is string argument
string of characters
May be called with or without arguments
Console.WriteLine( );
Console.WriteLine(“WriteLine( ) is a method.”);
Console.Write(“Main( ) is a method.”);
C# Programming: From Problem Analysis to Program Design

28. Program Statements (continued)
Read( ) accepts one character from the input device
ReadLine( ) accepts string of characters from the input device
Until the enter key is pressed
Write( ) does not automatically advance to next line
Write(“An example\n”);
Same as WriteLine(“An example”);
Includes special escape sequences
C# Programming: From Problem Analysis to Program Design

29. Program Statements (continued)
Special characters enclosed in double quotes
C# Programming: From Problem Analysis to Program Design

30. C# Elements Figure 2-4 Relationship among C# elements
C# Programming: From Problem Analysis to Program Design

31. Installing .NET Framework
.NET Framework must be installed to:
Compile, build, and run a C# application
Can download Microsoft’s .NET Framework Software Development Kit (SDK)→free download
OR install Visual Studio software (from book)
Create a place to store your work
C# Programming: From Problem Analysis to Program Design

32. Installing .NET Framework (continued)
Use the Visual Studio Integrated Development Environment (IDE) → Built-in editor
Type your program statements
Use Visual Studio IDE → Built-in compiler
Check for syntax rule violations
Compiler generates a file with an .exe extension
Use Visual Studio IDE → Built-in debugger
Use Visual Studio IDE → Built-in executor
C# Programming: From Problem Analysis to Program Design

33. Create Console Application
Begin by opening Visual Studio
Create new project
Select New Project on the Start page
OR use File → New Project option
C# Programming: From Problem Analysis to Program Design

34. Create New Project Figure 2-6 Creating a console application
C# Programming: From Problem Analysis to Program Design

35. Code Automatically Generated
Figure 2-7 Code automatically generated by Visual Studio
C# Programming: From Problem Analysis to Program Design

36. Typing Your Program Statements
IntelliSense feature of the IDE
Change the name of the class and the source code filename
Use the Solution Explorer Window to change the source code filename
Select View → Solution Explorer
C# Programming: From Problem Analysis to Program Design

37. Rename Source Code Name
Clicking Yes causes the class name to also be renamed
Figure 2-8 Changing the source code name from Class1
C# Programming: From Problem Analysis to Program Design

38. Compile and Run Application
To Compile – click Build on the Build menu
To run or execute application – click Start or Start Without Debugging on the Debug menu
Shortcut – if execute code that has not been compiled, automatically compiles first
Start option does not hold output screen → output flashes quickly
Last statement in Main( ), add Console.Read( );
C# Programming: From Problem Analysis to Program Design

39. Build Visual Studio Project
Figure 2-9 Compilation of a project using Visual Studio
C# Programming: From Problem Analysis to Program Design

40. Running an Application
Figure 2-10 Execution of an application using Visual Studio
C# Programming: From Problem Analysis to Program Design

41. Debugging an Application
Types of errors
Syntax errors
Typing error
Misspelled name
Forget to end a statement with a semicolon
Run-time errors
Failing to fully understand the problem
More difficult to detect
C# Programming: From Problem Analysis to Program Design

42. Missing ending double quotation mark
Error Listing
Missing ending double quotation mark
Pushpin
Errors reported
Figure 2-12 Syntax error message listing
C# Programming: From Problem Analysis to Program Design

43. Creating an Application – ProgrammingMessage Example
Figure Problem specification sheet for the
ProgrammingMessage example
C# Programming: From Problem Analysis to Program Design

44. ProgrammingMessage Example (continued)
Figure 2-14 Prototype for the ProgrammingMessage example
C# Programming: From Problem Analysis to Program Design

45. ProgrammingMessage Example (continued)
Pseudocode would include a single line to display the message “Programming can be FUN!” on the output screen
Figure Algorithm for
ProgrammingMessage example
C# Programming: From Problem Analysis to Program Design

46. ProgrammingMessage Example (continued)
Figure 2-16 Recommended deletions
May want to remove the XML comments (lines beginning with ///)
Change the name
Delete [STAThread]
Depending on your current settings, you may not need to make some of these changes
Can replace with static void Main( )
Replace TODO: with your program statements
C# Programming: From Problem Analysis to Program Design

47. ProgrammingMessage Example (continued)
/* Programmer: [supply your name]
Date: [supply the current date]
Purpose: This class can be used to send messages to the output screen. */
using System;
namespace ProgrammingMessage {
class ProgrammingDisplay
static void Main( )
Console.WriteLine(“Programming can be”);
Console.WriteLine(“FUN!”);
Console.Read( ); }
Complete program listing
C# Programming: From Problem Analysis to Program Design

48. Chapter Summary Types of applications developed with C#
Web applications
Windows graphical user interface (GUI) applications
Console-based applications
Framework class library groups by namespaces
Namespaces group classes
Classes have methods
Methods include program statements
C# Programming: From Problem Analysis to Program Design

49. Chapter Summary (continued)
Visual Studio includes .NET Framework
Editor tool, compiler, debugger, and executor
Compile using Build
Run using Start or Start without Debugging
Debugging
Syntax errors
Run-time errors
Use five steps to program development to create applications
C# Programming: From Problem Analysis to Program Design