Storing pairs of integers

falled

falled

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Joined
Sep 16, 2006
Messages
20
Programming Experience
Beginner
I need a smart way to store pairs of integers, I've tried by using arrays of array but always give me some strange error of references or nullpointers

in my class i've been declared like this

VB.NET: 
[SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] List()() [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] nElements [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE]
 
[SIZE=2][COLOR=#0000ff]Public[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Sub[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]New[/COLOR][/SIZE][SIZE=2]([/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] nEl [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE][SIZE=2])[/SIZE]
[SIZE=2]List = [/SIZE][SIZE=2][COLOR=#0000ff]New[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE][SIZE=2](nEl)() {}[/SIZE]
[SIZE=2]List(nEl) = [/SIZE][SIZE=2][COLOR=#0000ff]New[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE][SIZE=2](2) {}[/SIZE]
[SIZE=2]nElements = nEl[/SIZE]
[SIZE=2][COLOR=#0000ff]End[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Sub[/COLOR][/SIZE]

And then I try to put the elements in the array, looking to not point to the out of the array.

There's any other way to create a structure of pairs of integers, there's any kind of struct?

Thank you all and Sorry For my bad english

Visca el barça
 
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Try this:

VB.NET: 
<System.Serializable()> Public Class IntPair
    Private _x, _y As Integer

    Public Property X() As Integer
        Get
            Return _x
        End Get
        Set(ByVal value As Integer)
            _x = value
        End Set
    End Property

    Public Property Y() As Integer
        Get
            Return _y
        End Get
        Set(ByVal value As Integer)
            _y = value
        End Set
    End Property

    Public Sub New()
        _x = 0
        _y = 0
    End Sub

    Public Sub New(ByVal x, ByVal y)
        _x = x
        _y = y
    End Sub
End Class
VB.NET: 
<System.Serializable()> Public Class PairsCollection
    Implements ICollection(Of IntPair)

    Private collection As New ArrayList

    Public ReadOnly Property Pair(ByVal index As Integer) As IntPair
        Get
            Return CType(collection(index), IntPair)
        End Get
    End Property


    Public Sub Add(ByVal item As IntPair) Implements System.Collections.Generic.ICollection(Of IntPair).Add
        collection.Add(item)
    End Sub

    Public Sub Clear() Implements System.Collections.Generic.ICollection(Of   IntPair).Clear
        collection.Clear()
    End Sub

    Public Function Contains(ByVal item As IntPair) As Boolean Implements System.Collections.Generic.ICollection(Of IntPair).Contains
        collection.Contains(item)
    End Function

    Public Sub CopyTo(ByVal array() As IntPair, ByVal arrayIndex As Integer) Implements System.Collections.Generic.ICollection(Of IntPair).CopyTo
        collection.CopyTo(array, arrayIndex)
    End Sub

    Public ReadOnly Property Count() As Integer Implements System.Collections.Generic.ICollection(Of IntPair).Count
        Get
            Return collection.Count
        End Get
    End Property

    Public ReadOnly Property IsReadOnly() As Boolean Implements System.Collections.Generic.ICollection(Of IntPair).IsReadOnly
        Get
            Return collection.IsReadOnly
        End Get
    End Property

    Public Function Remove(ByVal item As IntPair) As Boolean Implements System.Collections.Generic.ICollection(Of IntPair).Remove
        Try
            collection.Remove(item)
            Return True
        Catch ex As Exception
            Return False
        End Try
    End Function

    Public Function GetEnumerator() As System.Collections.Generic.IEnumerator(Of IntPair) Implements System.Collections.Generic.IEnumerable(Of IntPair).GetEnumerator
        Return collection.GetEnumerator()
    End Function

    Private Function GetEnumerator1() As System.Collections.IEnumerator Implements System.Collections.IEnumerable.GetEnumerator
        Return collection.GetEnumerator()
    End Function
End Class
Use like this:

VB.NET: 
Dim pc As New PairsCollection

pc.Add(new IntPair(1, 2))

' etc....

' to access the pairs...

pc.Pairs(<index>).X
pc.Pairs(<index>).Y
P.S. Classes are <Serializable()> in case you want to write the collection to a file.


Hope this helps you!
 
Upvote 0 Downvote
Even easier (PairsCollection class; use the same IntPair class):

VB.NET: 
<System.Serializable()> Public Class PairsCollection
    Inherits System.Collections.ObjectModel.Collection(Of IntPair)

End Class
Use like this:

VB.NET: 
Dim pc As New PairsCollection
pc.Add(New IntPair(x, y))
....
' access pairs
pc.Item(<index>).X
pc.Item(<index>).Y
 
Upvote 0 Downvote
or using the system.collections.generic
VB.NET: 
dim l as new list(of intpair)
l.add(New IntPair(x, y))
 
Upvote 0 Downvote
All your code works perfectly!!!!!!!!!

I wanted this method to create a collection of pairs, but i wanted to sort for the to fields too.

inserting (1,20),(2,30),(5,10),(1,5),(2,30),(2,5) the result should stay like that:

(1,5)
(1,20)
(2,5)
(2,30)
(2,30)
(5,10)

I added this 3 methods to the Inhereted collection class called PairCollection, and I only must add the elements by using:

addSorted(new Pair(1,20)
...

VB.NET: 
[SIZE=2][COLOR=#0000ff]Public[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Function[/COLOR][/SIZE][SIZE=2] Put([/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] item [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] IntPair, [/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] pos [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE][SIZE=2]) [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Boolean[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]If[/COLOR][/SIZE][SIZE=2] (pos < [/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].Count) [/SIZE][SIZE=2][COLOR=#0000ff]Then[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Try[/COLOR][/SIZE]
[SIZE=2]collection(pos) = item[/SIZE]
[SIZE=2][COLOR=#0000ff]Return[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]True[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Catch[/COLOR][/SIZE][SIZE=2] ex [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] Exception[/SIZE]
[SIZE=2]MessageBox.Show([/SIZE][SIZE=2][COLOR=#800000]"Put method failure"[/COLOR][/SIZE][SIZE=2])[/SIZE]
[SIZE=2][COLOR=#0000ff]Return[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]False[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]End[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Try[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]End[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]If[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]End[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Function[/COLOR][/SIZE]
VB.NET: 
[SIZE=2][COLOR=#0000ff]Public[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Sub[/COLOR][/SIZE][SIZE=2] AddSorted([/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] item [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] IntPair)[/SIZE]
[SIZE=2][COLOR=#0000ff]Try[/COLOR][/SIZE]
[SIZE=2]collection.Add(item)[/SIZE]
[SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] items [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE][SIZE=2] = [/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].Count - 1[/SIZE]
[SIZE=2][COLOR=#0000ff]If[/COLOR][/SIZE][SIZE=2] (items + 1) >= 2 [/SIZE][SIZE=2][COLOR=#0000ff]Then[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] finish [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Boolean[/COLOR][/SIZE][SIZE=2] = [/SIZE][SIZE=2][COLOR=#0000ff]False[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] m [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]For[/COLOR][/SIZE][SIZE=2] m = items [/SIZE][SIZE=2][COLOR=#0000ff]To[/COLOR][/SIZE][SIZE=2] 1 [/SIZE][SIZE=2][COLOR=#0000ff]Step[/COLOR][/SIZE][SIZE=2] -1[/SIZE]
[SIZE=2][COLOR=#0000ff]If[/COLOR][/SIZE][SIZE=2] ([/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].Pair(m).X < [/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].Pair(m - 1).X) [/SIZE][SIZE=2][COLOR=#0000ff]Then[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].Swap(m, m - 1)[/SIZE]
[SIZE=2][COLOR=#0000ff]ElseIf[/COLOR][/SIZE][SIZE=2] ([/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].Pair(m).X = [/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].Pair(m - 1).X) [/SIZE][SIZE=2][COLOR=#0000ff]Then[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]If[/COLOR][/SIZE][SIZE=2] ([/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].Pair(m).Y < [/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].Pair(m - 1).Y) [/SIZE][SIZE=2][COLOR=#0000ff]Then[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].Swap(m, m - 1)[/SIZE]
[SIZE=2][COLOR=#0000ff]End[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]If[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]End[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]If[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Next[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]End[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]If[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Catch[/COLOR][/SIZE][SIZE=2] ex [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] Exception[/SIZE]
[SIZE=2]collection.Add([/SIZE][SIZE=2][COLOR=#0000ff]New[/COLOR][/SIZE][SIZE=2] IntPair)[/SIZE]
[SIZE=2]MessageBox.Show([/SIZE][SIZE=2][COLOR=#800000]"AddSorted method failure, outIndex"[/COLOR][/SIZE][SIZE=2])[/SIZE]
[SIZE=2][COLOR=#0000ff]End[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Try[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]End[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Sub[/COLOR][/SIZE]
VB.NET: 
[SIZE=2][COLOR=#0000ff]Public[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Function[/COLOR][/SIZE][SIZE=2] Swap([/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] item1 [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE][SIZE=2], [/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] item2 [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE][SIZE=2]) [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Boolean[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] b [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Boolean[/COLOR][/SIZE][SIZE=2] = [/SIZE][SIZE=2][COLOR=#0000ff]False[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] item [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] IntPair = [/SIZE][SIZE=2][COLOR=#0000ff]New[/COLOR][/SIZE][SIZE=2] IntPair[/SIZE]
[SIZE=2][COLOR=#0000ff]If[/COLOR][/SIZE][SIZE=2] ([/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].Count > item1) [/SIZE][SIZE=2][COLOR=#0000ff]And[/COLOR][/SIZE][SIZE=2] ([/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].Count > item2) [/SIZE][SIZE=2][COLOR=#0000ff]Then[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Try[/COLOR][/SIZE]
[SIZE=2]item = [/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].Pair(item1)[/SIZE]
[SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].Put([/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].Pair(item2), item1)[/SIZE]
[SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].Put(item, item2)[/SIZE]
[SIZE=2][COLOR=#0000ff]Return[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]True[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Catch[/COLOR][/SIZE][SIZE=2] ex [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] Exception[/SIZE]
[SIZE=2]MessageBox.Show([/SIZE][SIZE=2][COLOR=#800000]"Swap method failure"[/COLOR][/SIZE][SIZE=2])[/SIZE]
[SIZE=2][COLOR=#0000ff]Return[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]False[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]End[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Try[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Else[/COLOR][/SIZE]
[SIZE=2]MessageBox.Show([/SIZE][SIZE=2][COLOR=#800000]"Swap method failure, outIndex"[/COLOR][/SIZE][SIZE=2])[/SIZE]
[SIZE=2][COLOR=#0000ff]Return[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]False[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]End[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]If[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]End[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Function[/COLOR][/SIZE]


Thank you all and sorry for my bad writting, If you think I can improve this methods just tell me, and if I made some mistake while writting tell me it to!!

Visca el BARÇA!!!!
 
Upvote 0 Downvote
Add this class:
VB.NET: 
    Public Class IntPairSort
        Implements IComparer(Of IntPair)
 
        Public Function Compare(ByVal x As IntPair, ByVal y As IntPair) As Integer _
        Implements System.Collections.Generic.IComparer(Of IntPair).Compare
            Return x.X < y.Y
        End Function
    End Class
Now you can sort the list on the fly like this:
VB.NET: 
        Dim l As New List(Of IntPair)
        l.Add(New IntPair(1, 2))
        l.Add(New IntPair(5, 4))
        l.Add(New IntPair(3, 8))
        l.Add(New IntPair(1, 1))
        l.Sort(New IntPairSort)
 
Upvote 0 Downvote

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