в 16:40, 26 мая 2010

2010-05-26T16:40:06Z

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2010-05-26T12:45:48Z

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==Array IndexOf and LastIndexOf==

<source lang="vbnet">
Imports System
Public Class MainClass

Shared Sub Main(ByVal args As String())
Dim values(10) As Integer
For i As Integer = 0 To 10
values(i) = i
Next i
Console.WriteLine(Array.IndexOf(values, 6).ToString)
Console.WriteLine(Array.LastIndexOf(values, 3).ToString)
End Sub
End Class

</source>

==Array Length Property==

<source lang="vbnet">
Imports System
Imports System.Diagnostics

Public Class MainClass
Shared Sub Main()
Dim arr(99) As Integer
For i As Integer = 0 To 99
arr(i) = i * i
Next i
Console.WriteLine(arr.Length)
End Sub
End Class

</source>

==Array Performance Test: One-dimensional array==

<source lang="vbnet">
Imports System
Imports System.Collections
Public Class MainClass

Shared Sub Main(ByVal args As String())
Dim start_time As DateTime
Dim stop_time As DateTime
Dim elapsed_time As TimeSpan
" Get the number of items.
Dim num_items As Integer = 10000
" One-dimensional array.
Dim array1(0 To num_items - 1) As Integer
start_time = Now
For i As Integer = 0 To num_items - 1
array1(i) = i
Next i
stop_time = Now
elapsed_time = stop_time.Subtract(start_time)
Console.WriteLine( elapsed_time.TotalSeconds().ToString )
End Sub
End Class

</source>

==Array Performance Test: SetValue(i, i)==

<source lang="vbnet">
Imports System
Imports System.Collections
Public Class MainClass

Shared Sub Main(ByVal args As String())
Dim start_time As DateTime
Dim stop_time As DateTime
Dim elapsed_time As TimeSpan
" Get the number of items.
Dim num_items As Integer = 1000000
" One-dimensional Array.
Dim array3 As Array = _
Array.CreateInstance(GetType(Integer), num_items)
start_time = Now
For i As Integer = 0 To num_items - 1
array3.SetValue(i, i)
Next i
stop_time = Now
elapsed_time = stop_time.Subtract(start_time)
Console.WriteLine( elapsed_time.TotalSeconds().ToString )

End Sub
End Class

</source>

==Array UBound==

<source lang="vbnet">

Public Class MainClass
Public Shared Sub Main()
Dim arrMyIntArray1(20) As Integer
Dim arrMyIntArray2() As Integer = {1, 2, 3, 4}
Dim arrMyIntArray3(4, 2) As Integer
Dim arrMyIntArray4(,) As Integer = _
{{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}, {13, 14, 15, 16}}
Dim arrMyIntArray5() As Integer
Console.WriteLine(CStr(UBound(arrMyIntArray2)))
arrMyIntArray2.GetUpperBound(0)
Dim intLoop1 As Integer
Dim intLoop2 As Integer
For intLoop1 = 0 To UBound(arrMyIntArray4)
For intLoop2 = 0 To UBound(arrMyIntArray4, 2)
Console.WriteLine(arrMyIntArray4(intLoop1, intLoop2).ToString)
Next
Next

End Sub
End Class

</source>

==Array Upper Bound and Lower Bound==

<source lang="vbnet">
Imports System
Public Class MainClass
Shared Sub Main(ByVal args As String())
Dim friends() As String = {"1", "2", "3","4", "5"}
Console.WriteLine("Upper bound: " & UBound(friends), "Array Demo")
Console.WriteLine("Lower bound: " & LBound(friends), "Array Demo")
Array.Sort(friends)
Dim upperBound As Integer = friends.Length
Dim random As New System.Random()
Dim n As Integer
For n = 1 To 10
Dim index As Integer = random.Next(upperBound)
Console.WriteLine(index & ": " & friends(index))
Next
End Sub

End Class

</source>

==A simple class to store in the array==

<source lang="vbnet">
Imports System
Public Class MainClass

Shared Sub Main()
Dim intArray As Integer( )
Dim empArray As Employee( )
intArray = New Integer(5) {}
empArray = New Employee(3) {}
"populate the array
Dim i As Integer
"for indices 0 through 3
For i = 0 To empArray.Length - 1
empArray(i) = New Employee(i + 5)
i = i + 1
Next
End Sub
End Class

Public Class Employee
Private empID As Integer
"constructor
Public Sub New(ByVal empID As Integer)
Me.empID = empID
End Sub
End Class

</source>

==Bounded array Example==

<source lang="vbnet">
Imports System
Imports System.Data
Imports System.Collections
public class MainClass
Shared Sub Main()
Dim X As Array
Dim I As Integer
Dim Lengths(0) As Integer
Dim LowerBounds(0) As Integer
Lengths(0) = 10
LowerBounds(0) = 1
X = Array.CreateInstance(GetType(System.Int32), Lengths, LowerBounds)
Try
X.SetValue(5, 0)
Catch e As Exception
Console.WriteLine(e.Message)
End Try
X.SetValue(6, 1)
Console.WriteLine(X.GetValue(1))
End Sub
End Class

</source>

==Declare an Array and reference its member==

<source lang="vbnet">
Imports System
Public Class MainClass
Shared Sub Main()
"Declare an array
Dim strFriends(4) As String
"Populate the array
strFriends(0) = "R"
strFriends(1) = "B"
strFriends(2) = "S"
strFriends(3) = "S"
strFriends(4) = "K"
"Add the first array item to the list
System.Console.WriteLine(strFriends(0))
End Sub
End Class

</source>

==Declaring, allocating and initializing arrays==

<source lang="vbnet">
Imports System
Public Class MainClass
Shared Sub Main(ByVal args As String())
Dim i As Integer
Dim array As Integer() " declare array variable
Dim array1, array2 As Integer() " declare two arrays
array = New Integer(9) {} " allocate memory for array
" initializer list specifies number of elements
" and value of each element
array1 = New Integer() {32, 27, 64, 18, 95, _
14, 90, 70, 60, 37}
" allocate array2 based on length of array1
array2 = New Integer(array1.GetUpperBound(0)) {}
" set values in array2 by a calculation
For i = 0 To array2.GetUpperBound(0)
array2(i) = 2 + 2 * i
Next
Console.WriteLine( "Subscript " & vbTab & "Array" & vbTab & _
"Array1" & vbTab & "Array2" & vbCrLf )
" display values in array
For i = 0 To array.GetUpperBound(0)
Console.WriteLine( i & vbTab & array(i) & vbTab & _
array1(i) & vbTab & array2(i) & vbCrLf )
Next
Console.WriteLine( vbCrLf & "The array contains " & _
array.Length & " elements." )
End Sub
End Class

</source>

==For Each loops through Array==

<source lang="vbnet">
Imports System
Public Class MainClass

Shared Sub Main()
Dim intArray As Integer( ) = {2, 4, 6, 8, 10}
Dim empArray As Employee( ) = _
{New Employee(5), New Employee(7), New Employee(9)}
Console.WriteLine("The Integer array...")
Dim theInt As Integer
For Each theInt In intArray
Console.WriteLine(theInt.ToString( ))
Next theInt
Console.WriteLine("The Employee array...")
Dim e As Employee
For Each e In empArray
Console.WriteLine(e.ToString( ))
Next e
End Sub
End Class
Public Class Employee
Private empID As Integer
"constructor
Public Sub New(ByVal empID As Integer)
Me.empID = empID
End Sub
End Class

</source>

==Free array"s memory==

<source lang="vbnet">
Imports System
Imports System.Collections
Public Class MainClass

Shared Sub Main(ByVal args As String())
" Get the number of items.
Dim num_items As Integer = 10000
" One-dimensional array.
Dim array1(0 To num_items - 1) As Integer
For i As Integer = 0 To num_items - 1
array1(i) = i
Next i
" Free the first array"s memory.
Erase array1
End Sub
End Class

</source>

==Init an Array in Declaration==

<source lang="vbnet">
Imports System
Public Class MainClass
Shared Sub Main(ByVal args As String())
Dim friends() As String = {"1", "2", "3","4", "5"}

Dim upperBound As Integer = friends.Length
Dim random As New System.Random()
Dim n As Integer
For n = 1 To 10
Dim index As Integer = random.Next(upperBound)
Console.WriteLine(index & ": " & friends(index))
Next
End Sub

End Class

</source>

==Reference an Element in an Array by Index==

<source lang="vbnet">
Imports System
Public Class MainClass
Shared Sub Main(ByVal args As String())
Dim friends(4) As String
friends(0) = "1"
friends(1) = "2"
friends(2) = "3"
friends(3) = "4"
friends(4) = "5"
Console.WriteLine(friends(2))
End Sub

End Class

</source>

==Set Array Element Value by Index==

<source lang="vbnet">
Imports System

Public Class MainClass
Shared Sub Main()
Dim anArray As Array
Dim l(0) As Integer
Dim lowerBounds(0) As Integer
l(0) = 7
lowerBounds(0) = 1995
"creates an array of objects numbered 1995 - 2002
anArray = Array.CreateInstance(GetType(System.Int32), l, lowerBounds)
anArray.SetValue(200000, 1995)
anArray.SetValue(1000000, 2001)
Console.WriteLine("The entry in position 1995 is " & _
(anArray.GetValue(1995).ToString))
Console.WriteLine("The entry in position 2002 is " & _
(anArray.GetValue(2001).ToString))
End Sub
End Class

</source>

==Store your won Class in an Array==

<source lang="vbnet">
Imports System
Public Class MainClass
Shared Sub Main(ByVal args As String())
Dim intArray As Integer()
Dim empArray As Employee()
intArray = New Integer(5) {}
empArray = New Employee(3) {}
" populate the array
Dim i As Integer
" for indices 0 through 3
For i = 0 To empArray.Length - 1
empArray(i) = New Employee(i + 5)
i = i + 1
Next
End Sub
End Class
Public Class Employee
Private empID As Integer
" constructor
Public Sub New(ByVal empID As Integer)
Me.empID = empID
Console.WriteLine(empID)
End Sub
End Class

</source>

==Two ways to loop through Array==

<source lang="vbnet">
Imports System
Public Class MainClass

Shared Sub Main()
Dim intArray( ) As Integer
Dim empArray( ) As Employee
intArray = New Integer(5) {}
empArray = New Employee(3) {}
"populate the array
Dim i As Integer
For i = 0 To empArray.Length - 1
empArray(i) = New Employee(i + 5)
Next i
Console.WriteLine("The Integer array...")
Dim intValue As Integer
For Each intValue In intArray
Console.WriteLine(intValue.ToString( ))
Next
Console.WriteLine("The Employee array...")
Dim e As Employee
For Each e In empArray
Console.WriteLine(e)
Next
End Sub
End Class
Public Class Employee
Private empID As Integer
"constructor
Public Sub New(ByVal empID As Integer)
Me.empID = empID
End Sub
End Class

</source>

==Use Array CreateInstance to Create Array==

<source lang="vbnet">
Imports System
Public Class MainClass

Shared Sub Main(ByVal args As String())
Dim values As Array = _
Array.CreateInstance(GetType(Integer), 11)
For i As Integer = 0 To 10
values.SetValue(i, i)
Next i

Console.WriteLine(Array.IndexOf(values, 6).ToString)
Console.WriteLine(Array.LastIndexOf(values, 3).ToString)
End Sub
End Class

</source>

==Use For Each/Next to find a minimum grade==

<source lang="vbnet">
Imports System
Public Class MainClass
Shared Sub Main(ByVal args As String())
Dim gradeArray As Integer(,) = New Integer(,) {{1, 2, 3, 4}, {4, 3, 8, 1}, {7, 9, 8, 1}}
Dim grade As Integer
Dim lowGrade As Integer = 100
For Each grade In gradeArray
If grade < lowGrade Then
lowGrade = grade
End If
Next
Console.WriteLine("The minimum grade is: {0}", lowGrade)
End Sub
End Class

</source>

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в 16:40, 26 мая 2010

Admin: 1 версия