1. Advanced Programming C#
Introduction

2. Application Types Console Application Windows Application Service
Has standard streams (out, in, err)
GUI can be added manually
Windows Application
GUI based
No standard streams (out, in, err)
Main thread is shared by the GUI message pump & your code
Service
Main thread is commandeered by the SCM
No GUI

3. Start Visual Studio

4. New Project

5. Windows Application

6. Simple Program – console application
// A first program in C#.
using System;
class Welcome1 {
static void Main( string[] args )
Console.WriteLine( "Welcome to C# Programming!" );
} }

7. Constructions of Note using namespace class
like import in Java: bring in namespaces
namespace
disambiguation of names
like Internet hierarchical names and C++ naming
class
like in C++ or Java
single inheritance up to object

8. Constructions of Note static void Main() Console.Write(Line)
Defines the entry point for an assembly.
Four different overloads – taking string arguments and returning int’s.
Console.Write(Line)
Takes a formatted string: “Composite Format”
Indexed elements: e.g., {0}
can be used multiple times
only evaluated once
{index [,alignment][:formatting]}

9. Common Type System (CTS)
From MSDN

10. Atomic Data

11. Simple Program: Add Integers
Primitive data types
Data types that are built into C#
string, int, double, char, long
Console.ReadLine()
Used to get a value from the user input
Int32.Parse()
Used to convert a string argument to an integer
Allows math to be preformed once the string is converted

12. Built-in Types C# predefined types The “root” object Logical bool
Signed sbyte, short, int, long
Unsigned byte, ushort, uint, ulong
Floating-point float, double, decimal
Textual char, string
Textual types use Unicode (16-bit characters)

13. Types Unified Type System
Value types
Directly contain data
Cannot be null
Reference types
Contain references to objects
May be null
In C# you have value types that directly hold the data on the stack and reference types that keeps a reference on the stack, but allocates the real memory on the heap.
Also have pointer types in unsafe code. Will discuss those in Part 2.
int i = 123;
string s = "Hello world";
123 i s
"Hello world"

14. Programs
Write a C program to read three integer numbers and find their average.

15. Predefined Types Value Types
All are predefined structs
Signed
sbyte, short, int, long
Unsigned
byte, ushort, uint, ulong
Character
char
Floating point
float, double, decimal
Logical
bool

16. Predefined Types Integral Types
C# Type
System Type
Size (bytes)
Signed?
sbyte
System.Sbyte 1
Yes
short
System.Int16 2
int
System.Int32 4
long
System.Int64 8
byte
System.Byte No
ushort
System.UInt16
uint
System.UInt32
ulong
System.UInt64

17. Predefined Types Floating Point Types
Follows IEEE 754 specification
Supports ± 0, ± Infinity, NaN
C# Type
System Type
Size (bytes)
float
System.Single 4
double
System.Double 8

18. Predefined Types decimal
128 bits
Essentially a 96 bit value scaled by a power of 10
Decimal values represented precisely
Doesn’t support signed zeros, infinities or NaN
C# Type
System Type
Size (bytes)
decimal
System.Decimal 16

19. Predefined Types bool Represents logical values
Literal values are true and false
Cannot use 1 and 0 as boolean values
No standard conversion between other types and bool
Eliminating implicit conversions between numbers and bool can help find subtle bugs.
C# Type
System Type
Size (bytes)
bool
System.Boolean
1 (2 for arrays)

20. Predefined Types char Represents a Unicode character Literals
‘A’ // Simple character
‘\u0041’ // Unicode
‘\x0041’ // Unsigned short hexadecimal
‘\n’ // Escape sequence character
C# Type
System Type
Size (bytes)
Char
System.Char 2

21. Predefined Types string
An immutable sequence of Unicode characters
Reference type
Special syntax for literals
string s = “I am a string”;
C# Type
System Type
Size (bytes)
String
System.String
20 minimum

22. Type System Value types Reference types Primitives int i;
Enums enum State { Off, On }
Structs struct Point { int x, y; }
Reference types
Classes class Foo: Bar, IFoo {...}
Interfaces interface IFoo: IBar {...}
Arrays string[] a = new string[10];
Delegates delegate void Empty();

23. Example
Assume you work for the Alexandria Electricity company and you need a program to help you calculate the electricity bill for each customer. The program input should be the old meter reading and the new meter reading. Given that the price is 0.10 pounds per kilowatt.

24. Program Structure Main Method
Execution begins at the static Main() method
Can have only one method with one of the following signatures in an assembly
static void Main()
static int Main()
static void Main(string[] args)
static int Main(string[] args)

25. C# Comments Comments can be created using //…
Multi-lines comments use /* … */
Comments are ignored by the compiler

26. Program Structure Syntax
Identifiers
Names for types, methods, fields, etc.
Must be whole word – no white space
Unicode characters
Begins with letter or underscore
Case sensitive
Must not clash with keyword
Unless prefixed

27. Identifiers: Keywords
Often we use special identifiers called keywords that already have a predefined meaning in the language
Example: class
A keyword cannot be used in any other way
All C# keywords are lowercase!

28. Arithmetic Arithmetic operations Asterisk (*) is multiplication
Slash (/) is division
Percent sign (%) is the modulus operator
Plus (+) and minus (-) are the same
There are no exponents

29. Operators Associativity
Assignment and ternary conditional operators are right-associative
Operations performed right to left
x = y = z evaluates as x = (y = z)
All other binary operators are left-associative
Operations performed left to right
x + y + z evaluates as (x + y) + z
Use parentheses to control order

30. C# Keywords Words that cannot be used as variable or class names
Have a specific unchangeable function within the language
Example: class

31. C# Classes
Class names can only be one word long (i.e. no white space in class name )
Class names are capitalized, with each additional English word capitalized as well (e.g., MyFirstProgram )
Each class name is an identifier
Can contain letters, digits, and underscores (_)
Cannot start with digits
Can start with the at symbol

32. C# Class Methods Class bodies start with a left brace ({)
Class bodies end with a right brace (})
Methods
Building blocks of programs
The Main method
Each console or windows application must have exactly one
All programs start by executing the Main method
Braces are used to start ({) and end (}) a method

33. C# Statements Anything in quotes (“) is considered a string
Every statement must end in a semicolon (;)

34. C#

35. NameSpaces
You import namespaces when you want to be able to refer to classes by their short name, rather than full name
For example, import System.XML allows XmlDataDocument and XmlNode rather than System.XML.XmlDataDocument and System.XML.XmlNode to be in your code.

36. Program Structure Namespaces
namespace N1 {     // N1
class C1 {   // N1.C1
class C2 {   // N1.C1.C2
}    
namespace N2 {    // N1.N2
class C2 { // N1.N2.C2     }
The comments show the fully qualified names.
A namespace called N3.N4 is like two nested namespaces.

37. Program Structure Namespaces
The using statement lets you use types without typing the fully qualified name
Can always use a fully qualified name
using N1;
C1 a; // The N1. is implicit
N1.C1 b; // Fully qualified name
C2 c; // Error! C2 is undefined
N1.N2.C2 d; // One of the C2 classes
C1.C2 e; // The other one
Note that it is N1.C1, not N1::C1
The using statement is scoped by the namespace and/or compilation module containing it.

38. Program Structure Namespaces
Best practice: Put all of your types in a unique namespace
Have a namespace for your company, project, product, etc.
Look at how the .NET Framework classes are organized

39. Namespaces Partition the name space to avoid name conflict!
All .NET library code are organized using namespaces!
By default, C# code is contained in the global namespace
To refer to code within a namespace, must use qualified name (as in System.Console) or import explicitly (as in using System; )
using System;
class HelloWorld {
static void Main(string[] args)
Console.WriteLine(“Hello World!”); }
class HelloWorld {
static void Main(string[] args)
System.Console.WriteLine(“Hello World!”); }

40. Welcome4.cs // Printing multiple lines in a dialog Box. using System;
using System.Windows.Forms;
class Welcome4 {
static void Main( string[] args )
MessageBox.Show( "Welcome \n to \n C# \n programming!" );} }

41. Statements Overview Loop Statements Statement lists Block statements
while do
for
foreach
Jump Statements
break
continue
goto
return
throw
Exception handling
try
Statement lists
Block statements
Labeled statements
Declarations
Constants
Variables
Expression statements
checked, unchecked
lock
using
Conditionals if
switch

42. Statements Expression Statements
Statements must do work
Assignment, method call, ++, --, new
static void Main() {
int a, b = 2, c = 3;
a = b + c;
a++;
Console.WriteLine(a + b + c);
a == 2; // ERROR! }
Expression statements must do work.

43. Events
Events are a way for an object to communicate with those that are interested in what it has to offer, like a button has a click event
Interested parties use Event Handlers, which are a way of subscribing to the event

44. Math Class Methods The Math class
Allows the user to perform common math calculations
Using methods
ClassName.MethodName( argument1, arument2, … )
Constants
Math.PI = …
Math.E = …

45. Math Class Methods

46. Example
A motor car uses 8 liters of fuel per 100 km on normal roads and 15% more fuel on rough roads. Write a program to print out the distance the car can travel on full tank of 40 liters of fuel on both normal and rough roads.

47. Statements Variables and Constants
static void Main() {
const float pi = 3.14f;
const int r = 123;
Console.WriteLine(pi * r * r);
int a;
int b = 2, c = 3;
a = 1;
Console.WriteLine(a + b + c); }

48. Example
Write a program to ask you for the temperature in Fahrenheit and then convert it to Celsius. Given:
C= 5/9 (F-32)
Write a program to ask you for the temperature in Celsius and then convert it to Fahrenheit.

49. Programs
Write a program to ask a person for his height in feet and inches and then tell them his height in cms. Given that 1 foot = 30 cms and 1 inch = 2.5 cms.

50. Examples
Write a program to ask the user for the width and length of a piece of land and then tell him how many orange trees he can grow on it. Given that each orange tree requires 4 m2.

51. Examples
Write a program to ask the user for the radius of a circle, and then display its area and circumference.