// Single line
/* Multiple
line */
/// <summary>XML comments on single line</summary>
/** <summary>XML comments on multiple lines</summary> */

Value Types
Boolean
Byte,SByte
Char
Short,UShort,Integer,UInteger,Long,ULong
Single,Double
Decimal
Date

Reference Types
Object
String

Initializing
Dim correct As Boolean = True
Dim b As Byte = &H2A'hex or &O52 for octal
Dim person As Object = Nothing
Dim name As String = "Dwight"
Dim grade As Char = "B"c
Dim today As Date = #12/31/2007 12:15:00 PM#
Dim amount As Decimal = 35.99@
Dim gpa As Single = 2.9!
Dim pi As Double = 3.14159265
Dim lTotal As Long = 123456L
Dim sTotal As Short = 123S
Dim usTotal As UShort = 123US
Dim uiTotal As UInteger = 123UI
Dim ulTotal As ULong = 123UL

Implicitly Typed Local Variables
Dim s = "Hello!"
Dim nums = New Integer() {1,2,3}
Dim hero = New SuperHero With {.Name = "Batman"}

Type Information
DimxAsInteger
Console.WriteLine(x.GetType())' Prints System.Int32
Console.WriteLine(GetType(Integer))' Prints System.Int32
Console.WriteLine(TypeName(x))' Prints Integer

Dim c as New Circle
IfTypeOfcIsShape Then _
Console.WriteLine("c is a Shape")

Type Conversion / Casting
Dim d As Single = 3.5
Dim i As Integer =CType(d,Integer)' set to 4 (Banker's rounding)
i =CInt(d)' same result as CType
i =Int(d)' set to 3 (Int function truncates the decimal)

Dim o As Object = 2
i =DirectCast(o,Integer)' Throws InvalidCastException if type cast fails

Dim s As New Shape
Dim c As Circle =TryCast(s,Circle)' Returns Nothing if type cast fails

Value Types
bool
byte,sbyte
char
short,ushort,int,uint,long,ulong
float,double
decimal
DateTime(not a built-in C# type)

Reference Types
object
string

Initializing
bool correct = true;
byte b = 0x2A;// hex
object person = null;
string name = "Dwight";
char grade = 'B';
DateTime today = DateTime.Parse("12/31/2007 12:15:00");
decimal amount = 35.99m;
float gpa = 2.9f;
double pi = 3.14159265;
long lTotal = 123456L;
short sTotal = 123;
ushort usTotal = 123;
uint uiTotal = 123;
ulong ulTotal = 123;

Implicitly Typed Local Variables
var s = "Hello!";
var nums = new int[] { 1,3 };
var hero = new SuperHero() { Name = "Batman" };

Type Information
int x;
Console.WriteLine(x.GetType());// Prints System.Int32
Console.WriteLine(typeof(int));// Prints System.Int32
Console.WriteLine(x.GetType().Name);// prints Int32

Circle c = new Circle();
if (cisShape)
Console.WriteLine("c is a Shape");

Type Conversion / Casting
float d = 3.5f;
i =Convert.ToInt32(d);// Set to 4 (rounds)
int i =(int)d;// set to 3 (truncates decimal)


object o = 2;
int i = (int)o;// Throws InvalidCastException if type cast fails

Shape s = new Shape();
Circle c = sasCircle;// Returns null if type cast fails

' Can set to a const or var; may be initialized in a constructor
ReadOnlyMIN_DIAMETERAsSingle = 4.93

// Can set to a const or var; may be initialized in a constructor
readonlyfloat MIN_DIAMETER = 4.93f;

Comparison
= < > <= >= <>

Arithmetic
+ - * /
Mod
/(integer division)
^(raise to a power)

Assignment
= += -= *= /= /= ^= <<= >>= &=

Bitwise
And Or Xor Not << >>

Logical
AndAlso OrElse And Or Xor Not

Note:AndAlso and OrElse perform short-circuit logical evaluations

String Concatenation
&

Comparison
== < > <= >= !=

Arithmetic
+ - * /
%(mod)
/(integer division if both operands are ints)
Math.Pow(x,y)

Assignment
= += -= *= /= %= &= |= ^= <<= >>= ++ --

Bitwise
& | ^ ~ << >>

Logical
&& || & | ^ !

Note:&& and || perform short-circuit logical evaluations

String Concatenation
+

' Ternary/Conditional operator (Iff evaluates 2nd and 3rd expressions)
greeting =If(age < 20,"What's up?","Hello")

' One line doesn't require "End If"
Ifage < 20Thengreeting = "What's up?"
Ifage < 20Thengreeting = "What's up?"Elsegreeting = "Hello"

' Use : to put two commands on same line
Ifx <> 100 AndAlso y < 5Thenx *= 5:y *= 2

' Preferred
Ifx <> 100 AndAlso y < 5Then
x *= 5
y *= 2
End If

' To break up any long single line use _
IfwhenYouHaveAReally < longLine And _
itNeedsToBeBrokenInto2 > LinesThen_
UseTheUnderscore(charToBreakItUp)

'Ifx > 5Then
x *= y
ElseIfx = 5 OrElse y Mod 2 = 0Then
x += y
ElseIfx < 10Then
x -= y
Else
x /= y
End If

Select Casecolor' Must be a primitive data type
Case"pink","red"
r += 1
Case"blue"
b += 1
Case"green"
g += 1
Case Else
other += 1
End Select

// Ternary/Conditional operator
greeting = age < 20?"What's up?":"Hello";

if(age < 20)
greeting = "What's up?";
else
greeting = "Hello";

// Multiple statements must be enclosed in {}
if(x != 100 && y < 5) {
x *= 5;
y *= 2;
}

No need for _ or : since ; is used to terminate each statement.

if(x > 5)
x *= y;
elseif (x == 5 || y % 2 == 0)
x += y;
elseif (x < 10)
x -= y;
else
x /= y;

// Every case must end with break or goto case
switch(color) {// Must be integer or string
case"pink":
case"red": r++;break;
case"blue": b++;break;
case"green": g++;break;
default: other++;break;// break necessary on default
}

' Array or collection looping
Dim names As String() = {"Fred","Sue","Barney"}
For Eachs As StringInnames
Console.WriteLine(s)
Next

' Breaking out of loops
Dim i As Integer = 0
While (True)
If (i = 5) ThenExit While
i += 1
End While

' Continue to next iteration
For i = 0 To 4
If i < 4 ThenContinue For
Console.WriteLine(i)' Only prints 4
Next

// no "until" keyword
while(c < 10)
c++;


for(c = 2; c <= 10; c += 2)
Console.WriteLine(c);

Post-test Loop:

do
c++;
while(c < 10);

// Array or collection looping
string[] names = {"Fred","Barney"};
foreach(string sinnames)
Console.WriteLine(s);

// Breaking out of loops
int i = 0;
while (true) {
if (i == 5)
break;
i++;
}

// Continue to next iteration
for (i = 0; i < 5; i++) {
if (i < 4)
continue;
Console.WriteLine(i);// Only prints 4
}

Dim nums()As Integer = {1,3}
For i As Integer = 0 To nums.Length - 1
Console.WriteLine(nums(i))
Next

' 4 is the index of the last element,so it holds 5 elements
Dim names(4) As String
names(0) = "David"
names(5) = "Bobby"' Throws System.IndexOutOfRangeException

' Resize the array,keeping the existing values (Preserve is optional)
ReDim Preservenames(6)

Dim twoD(rows-1,cols-1) As Single
twoD(2,0) = 4.5

Dim jagged()()As Integer = { _
New Integer(4) {},New Integer(1) {},New Integer(2) {} }
jagged(0)(4) = 5

int[]nums = {1,3};
for (int i = 0; i < nums.Length; i++)
Console.WriteLine(nums[i]);


// 5 is the size of the array
string[] names = new string[5];
names[0] = "David";
names[5] = "Bobby";// Throws System.IndexOutOfRangeException


// C# can't dynamically resize an array. Just copy into new array.
string[] names2 = new string[7];
Array.Copy(names,names2,names.Length);// or names.CopyTo(names2,0);

float[,]twoD = new float[rows,cols];
twoD[2,0] = 4.5f;

int[][]jagged = new int[3][] {
new int[5],new int[2],new int[3] };
jagged[0][4] = 5;

' Pass by value (in,default),reference (in/out),and reference (out)
SubTestFunc(ByValx As Integer,ByRefy As Integer,ByRefz As Integer)
x += 1
y += 1
z = 5
End Sub

Dim a = 1,b = 1,c As Integer' c set to zero by default
TestFunc(a,b,c)
Console.WriteLine("{0} {1} {2}",a,c)' 1 2 5

' Accept variable number of arguments
FunctionSum(ByValParamArraynumsAsInteger()) As Integer
Sum = 0
For Each i As Integer In nums
Sum += i
Next
End Function' Or use Return statement like C#

Dim total As Integer = Sum(4,3,1)' returns 10

' Optional parameters must be listed last and must have a default value
SubSayHello(ByVal name As String,OptionalByVal prefix As String = "")
Console.WriteLine("Greetings," & prefix & " " & name)
End Sub

SayHello("Strangelove","Dr.")
SayHello("Mom")

int a = 1,c;// c doesn't need initializing
TestFunc(a,refb,outc);
Console.WriteLine("{0} {1} {2}",c);// 1 2 5

// Accept variable number of arguments
int Sum(paramsint[] nums) {
int sum = 0;
foreach (int i in nums)
sum += i;
return sum;
}

int total = Sum(4,1);// returns 10

/* C# 4.0 supports optional parameters. PrevIoUs versions required function overloading. */
void SayHello(string name,string prefix = "") {
Console.WriteLine("Greetings," + prefix + " " + name);
}

SayHello("Strangelove","Dr.");
SayHello("Mom");

Special character constants (all also accessible from ControlChars class)
vbCrLf,vbCr,vbLf,vbNewLine
vbNullString
vbTab
vbBack
vbFormFeed
vbVerticalTab
""

' String concatenation (use & or +)
Dim school As String = "Harding"&vbTab
school = school & "University"' school is "Harding (tab) University"

' Chars
Dim letter AsChar= school.Chars(0)' letter is H
letter = "Z"c' letter is Z
letter = Convert.tochar(65)' letter is A
letter =Chr(65)' same thing
Dim word() As Char = school.tocharArray()' word holds Harding

' No string literal operator
Dim msg As String = "File is c:/temp/x.dat"

' String comparison
Dim mascot As String = "Bisons"
If (mascot = "Bisons") Then' true
If (mascot.Equals("Bisons")) Then' true
If (mascot.ToUpper().Equals("BISONS")) Then' true
If (mascot.CompareTo("Bisons") = 0) Then' true

' String matching with Like - Regex is more powerful
If ("John 3:16"Like"Jo[Hh]? #:*") Then'true

' Substring
s = mascot.Substring(2,3))' s is "son"

' Replacement
s = mascot.Replace("sons","nomial"))' s is "Binomial"

' Split
Dim names As String = "Michael,Dwight,Jim,Pam"
Dim parts() As String = names.Split(",".tocharArray())' One name in each slot

' Date to string
Dim dt As New DateTime(1973,10,12)
Dim s As String = "My birthday: " & dt.ToString("MMM dd,yyyy")' Oct 12,1973

' Integer to String
Dim x As Integer = 2
Dim y As String = x.ToString()' y is "2"

' String to Integer
Dim x As Integer = Convert.ToInt32("-5")' x is -5

' Mutable string
Dim buffer As New System.Text.StringBuilder("two ")
buffer.Append("three ")
buffer.Insert(0,"one ")
buffer.Replace("two","TWO")
Console.WriteLine(buffer)' Prints "one TWO three"

Escape sequences
/r// carriage-return
/n// line-Feed
/t// tab
//// backslash
/"// quote

// String concatenation
stringschool = "Harding/t";
school = school + "University";// school is "Harding (tab) University"

// Chars
charletter = school[0];// letter is H
letter = 'Z';// letter is Z
letter = Convert.tochar(65);// letter is A
letter =(char)65;// same thing
char[]word = school.tocharArray();// word holds Harding

// String literal
string msg =@"File is c:/temp/x.dat";
// same as
string msg = "File is c://temp//x.dat";

// String comparison
string mascot = "Bisons";
if (mascot == "Bisons")// true
if (mascot.Equals("Bisons"))// true
if (mascot.ToUpper().Equals("BISONS"))// true
if (mascot.CompareTo("Bisons") == 0)// true

// String matching - No Like equivalent,use Regex

// Substring
s = mascot.Substring(2,3))// s is "son"

// Replacement
s = mascot.Replace("sons","nomial"))// s is "Binomial"

// Split
string names = "Michael,Pam";
string[] parts = names.Split(",".tocharArray());// One name in each slot

// Date to string
DateTime dt = new DateTime(1973,12);
string s = dt.ToString("MMM dd,yyyy");// Oct 12,1973

// int to string
int x = 2;
string y = x.ToString();// y is "2"

// Mutable string
System.Text.StringBuilderbuffer = new System.Text.StringBuilder("two ");
buffer.Append("three ");
buffer.Insert(0,"one ");
buffer.Replace("two","TWO");
Console.WriteLine(buffer);// Prints "one TWO three"

Imports System.Text.RegularExpressions

' Match a string pattern
Dim r As NewRegex("j[aeIoU]h?. /d:*",RegexOptions.IgnoreCase Or _
RegexOptions.Compiled)
If (r.Match("John 3:16").Success) Then'true
Console.WriteLine("Match")
End If

' Find and remember all matching patterns
Dim s As String = "My number is 305-1881,not 305-1818."
Dim r As New Regex("(/d+-/d+)")
Dim m AsMatch= r.Match(s)' Matches 305-1881 and 305-1818
While m.Success
Console.WriteLine("Found number: " & m.Groups(1).Value & " at position " _
& m.Groups(1).Index.ToString)
m = m.NextMatch()
End While

' Remeber multiple parts of matched pattern
Dim r As New Regex("(/d/d):(/d/d) (am|pm)")
Dim m As Match = r.Match("We left at 03:15 pm.")
If m.Success Then
Console.WriteLine("Hour: " & m.Groups(1).ToString)' 03
Console.WriteLine("Min: " & m.Groups(2).ToString)' 15
Console.WriteLine("Ending: " & m.Groups(3).ToString)' pm
End If

' Replace all occurrances of a pattern
Dim r As New Regex("h/w+?d",RegexOptions.IgnoreCase)
Dim s As String = r.Replace("I heard this was HARD!","easy")' I easy this was easy!

' Replace matched patterns
Dim s As String = Regex.Replace("123 < 456","(/d+) . (/d+)","$2 > $1")' 456 > 123

' Split a string based on a pattern
Dim names As String = "Michael,Pam"
Dim r As New Regex(",/s*")
Dim parts() As String = r.Split(names)' One name in each slot

using System.Text.RegularExpressions;

// Match a string pattern
Regexr = newRegex(@"j[aeIoU]h?. /d:*",RegexOptions.IgnoreCase |
RegexOptions.Compiled);
if (r.Match("John 3:16").Success)// true
Console.WriteLine("Match");

// Find and remember all matching patterns
string s = "My number is 305-1881,not 305-1818.";
Regex r = new Regex("(//d+-//d+)");
// Matches 305-1881 and 305-1818
for (Matchm = r.Match(s); m.Success; m = m.NextMatch())
Console.WriteLine("Found number: " + m.Groups[1] + " at position " +
m.Groups[1].Index);

// Remeber multiple parts of matched pattern
Regex r = new Regex("@(/d/d):(/d/d) (am|pm)");
Match m = r.Match("We left at 03:15 pm.");
if (m.Success) {
Console.WriteLine("Hour: " + m.Groups[1]);// 03
Console.WriteLine("Min: " + m.Groups[2]);// 15
Console.WriteLine("Ending: " + m.Groups[3]);// pm
}

// Replace all occurrances of a pattern
Regex r = new Regex("h//w+?d",RegexOptions.IgnoreCase);
string s = r.Replace("I heard this was HARD!","easy"));// I easy this was easy!

// Replace matched patterns
string s = Regex.Replace("123 < 456",@"(/d+) . (/d+)","$2 > $1");// 456 > 123

// Split a string based on a pattern
string names = "Michael,Pam";
Regex r = new Regex(@",/s*");
string[] parts = r.Split(names);// One name in each slot

' Throw an exception
Dim ex As New Exception("Something is really wrong.")
Throw ex

' Catch an exception
Try
y = 0
x = 10 / y
Catchex As ExceptionWheny = 0' Argument and When is optional
Console.WriteLine(ex.Message)
Finally
Beep()
End Try

' Deprecated unstructured error handling
OnErrorGoToMyErrorHandler
...
MyErrorHandler: Console.WriteLine(Err.Description)

// Throw an exception
Exception up = new Exception("Something is really wrong.");
throwup;// ha ha

// Catch an exception
try{
y = 0;
x = 10 / y;
}
catch(Exception ex) {// Argument is optional,no "When" keyword
Console.WriteLine(ex.Message);
}
finally{
Microsoft.VisualBasic.Interaction.Beep();
}

NamespaceHarding.Compsci.Graphics
...
End Namespace

' or

NamespaceHarding
NamespaceCompsci
NamespaceGraphics
...
End Namespace
End Namespace
End Namespace

ImportsHarding.Compsci.Graphics

namespaceHarding.Compsci.Graphics {
...
}

// or

namespaceHarding {
namespaceCompsci {
namespaceGraphics {
...
}
}
}

usingHarding.Compsci.Graphics;

Access Modifiers
Public
Private
Friend
Protected
Protected Friend

Class Modifiers
MustInherit
NotInheritable

Method Modifiers
MustOverride
NotInheritable
Shared
Overridable

' All members are Shared
Module

' Inheritance
ClassFootballGame
InheritsCompetition
...
End Class

' Interface definition
InterfaceIAlarmClock
...
End Interface

// Extending an interface
InterfaceIAlarmClock
InheritsIClock
...
End Interface

// Interface implementation
ClassWristWatch
ImplementsIAlarmClock,ITimer
...
End Class

Access Modifiers
public
private
internal
protected
protected internal

Class Modifiers
abstract
sealed
static

Method Modifiers
abstract
sealed
static
virtual

No Module equivalent - just use static class

// Inheritance
classFootballGame:Competition {
...
}

// Interface definition
interfaceIAlarmClock {
...
}

// Extending an interface
interfaceIAlarmClock:IClock {
...
}

// Interface implementation
classWristWatch:IAlarmClock,ITimer {
...
}

classSuperHero {
private int powerLevel;

public SuperHero() {
powerLevel = 0;
}

public SuperHero(int powerLevel) {
this.powerLevel = powerLevel;
}

static SuperHero() {
// Static constructor invoked before 1st instance is created
}

~SuperHero() {
// Destructor implicitly creates a Finalize method
}
}

Dim hero As SuperHero = New SuperHero
' or
Dim hero As New SuperHero

Withhero
.Name = "SpamMan"
.PowerLevel = 3
End With

hero.Defend("Laura Jones")
hero.Rest()' Calling Shared method
' or
SuperHero.Rest()

Dim hero2 As SuperHero = hero' Both reference the same object
hero2.Name = "WormWoman"
Console.WriteLine(hero.Name)' Prints WormWoman

hero =Nothing' Free the object

If heroIsNothingThen _
hero = New SuperHero

Dim obj As Object = New SuperHero
IfTypeOfobjIsSuperHero Then _
Console.WriteLine("Is a SuperHero object.")

' Mark object for quick disposal
Usingreader As StreamReader = File.OpenText("test.txt")
Dim line As String = reader.ReadLine()
While Not line Is Nothing
Console.WriteLine(line)
line = reader.ReadLine()
End While
End Using

SuperHero hero = new SuperHero();

// No "With" construct
hero.Name = "SpamMan";
hero.PowerLevel = 3;

hero.Defend("Laura Jones");
SuperHero.Rest();// Calling static method

SuperHero hero2 = hero;// Both reference the same object
hero2.Name = "WormWoman";
Console.WriteLine(hero.Name);// Prints WormWoman

hero =null;// Free the object

if (hero ==null)
hero = new SuperHero();

Object obj = new SuperHero();
if (objisSuperHero)
Console.WriteLine("Is a SuperHero object.");

StructureStudentRecord
Public name As String
Public gpa As Single

Public Sub New(ByVal name As String,ByVal gpa As Single)
Me.name = name
Me.gpa = gpa
End Sub
End Structure

Dim stu As StudentRecord = New StudentRecord("Bob",3.5)
Dim stu2 As StudentRecord = stu

stu2.name = "Sue"
Console.WriteLine(stu.name)' Prints Bob
Console.WriteLine(stu2.name)' Prints Sue

StudentRecord stu = new StudentRecord("Bob",3.5f);
StudentRecord stu2 = stu;

stu2.name = "Sue";
Console.WriteLine(stu.name);// Prints Bob
Console.WriteLine(stu2.name);// Prints Sue

' Auto-implemented properties are new to VB10
PublicPropertyName As String
PublicPropertySize As Integer = -1' Default value,Get and Set both Public

' Traditional property implementation
Private mName As String
PublicPropertyName() As String
Get
Return mName
End Get
Set(ByVal value As String)
mName = value
End Set
End Property

' Read-only property
Private mPowerLevel As Integer
PublicReadOnlyProperty PowerLevel() As Integer
Get
Return mPowerLevel
End Get
End Property

' Write-only property
Private mHeight As Double
PublicWriteOnlyProperty Height() As Double
Set(ByVal value As Double)
mHeight = If(value < 0,mHeight = 0,mHeight = value)
End Set
End Property

// Auto-implemented properties
public string Name {get; set;}
public int Size {get;protectedset;}// Set default value in constructor

// Traditional property implementation
private string name;
public string Name {
get{
return name;
}
set{
name = value;
}
}

// Read-only property
private int powerLevel;
public int PowerLevel {
get{
return powerLevel;
}
}

// Write-only property
private double height;
public double Height {
set{
height = value < 0 ? 0 : value;
}
}

DelegateSub MsgArrivedEventHandler(ByVal message As String)

EventMsgArrivedEvent As MsgArrivedEventHandler

' or to define an event which declares a delegate implicitly
EventMsgArrivedEvent(ByVal message As String)

AddHandlerMsgArrivedEvent,AddressOfMy_MsgArrivedCallback
' Won't throw an exception if obj is Nothing
RaiseEventMsgArrivedEvent("Test message")
RemoveHandlerMsgArrivedEvent,AddressOfMy_MsgArrivedCallback

Imports System.Windows.Forms

DimWithEventsMyButton As Button' WithEvents can't be used on local variable
MyButton = New Button

Private Sub MyButton_Click(ByVal sender As System.Object,_
ByVal e As System.EventArgs)HandlesMyButton.Click
MessageBox.Show(Me,"Button was clicked","Info",_
MessageBoxButtons.OK,MessageBoxIcon.Information)
End Sub

delegatevoid MsgArrivedEventHandler(string message);

eventMsgArrivedEventHandler MsgArrivedEvent;

// Delegates must be used with events in C#


MsgArrivedEvent+=new MsgArrivedEventHandler(My_MsgArrivedEventCallback);
MsgArrivedEvent("Test message");// Throws exception if obj is null
MsgArrivedEvent-=new MsgArrivedEventHandler(My_MsgArrivedEventCallback);

using System.Windows.Forms;

Button MyButton = new Button();
MyButton.Click += new System.EventHandler(MyButton_Click);

private void MyButton_Click(object sender,System.EventArgs e) {
MessageBox.Show(this,
MessageBoxButtons.OK,MessageBoxIcon.Information);
}

' Enforce accepted data type at compile-time
Dim numbers As New List(Of Integer)
numbers.Add(2)
numbers.Add(4)
DisplayList(Of Integer)(numbers)

' Subroutine can display any type of List
Sub DisplayList(Of T)(ByVal list As List(Of T)
For Each item AsTIn list
Console.WriteLine(item)
Next
End Sub

' Class works on any data type
Class SillyList(Of T)
Private list(10) AsT
Private rand As New Random

Public Sub Add(ByVal item AsT)
list(rand.Next(10)) = item
End Sub

Public Function GetItem() AsT
Return list(rand.Next(10))
End Function
End Class

' Limit T to only types that implement IComparable
Function Maximum(Of T As IComparable)(ByVal ParamArray items AsT()) AsT
Dim max AsT= items(0)
For Each item AsTIn items
If item.CompareTo(max) > 0 Then max = item
Next
Return max
End Function

// Enforce accepted data type at compile-time
List<int>numbers = new List<int>();
numbers.Add(2);
numbers.Add(4);
DisplayList<int>(numbers);

// Function can display any type of List
void DisplayList<T>(List<T>list) {
foreach (Titem in list)
Console.WriteLine(item);
}

// Class works on any data type
class SillyList<T>{
privateT[] list = newT[10];
private Random rand = new Random();

public void Add(Titem) {
list[rand.Next(10)] = item;
}

publicTGetItem() {
return list[rand.Next(10)];
}
}

// Limit T to only types that implement IComparable
TMaximum<T>(paramsT[] items)where T : IComparable<T>{
Tmax = items[0];
foreach (Titem in items)
if (item.CompareTo(max) > 0)
max = item;
return max;
}