Visual Basic

5-Jul-09 11:53

I need some assistance in sorting a structure array...

I am reading words from a text file and need to store them in a array:

Structure Translate
    Dim English As String
    Dim French As String
    Dim German As String
End Structure

Dim TWord(16) As Translate

I then read the text file.. which basically goes from English, to French, to German.
So the first line in the text file is the English word YES, the second line is OUI (French) which means YES and the third is JA (German) which means YES in English as well. So what I have to do it put these ina structured array.

fs = New FileStream("TranslateC.txt", FileMode.Open, FileAccess.Read)
sr = New StreamReader(fs)

count = 0
Do While sr.Peek() >= 0

    TWord(count).English = sr.ReadLine()
    TWord(count).French = sr.ReadLine()
    TWord(count).German = sr.ReadLine()
    count = count + 1
Loop
sr.Close()

Now that I have that.. they want me to sort the english words?!? This is where I get completely lost. I found code earlier that helped me and it sorted the english words from A to Z but none of the others. So the translated words did not match up.

*** Could anyone point me to the correct location of a good tutorial on this? ***

I did the project first hand (That works!) but used jagged arrays instead:
Peronsally I like this way better but according to the project it is not HOW they wanted it done:

Imports System.IO

Public Class Form1

    Dim TranslateWords(15)() As String

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim fs As FileStream
        Dim sr As StreamReader
        Dim count As Integer

        fs = New FileStream("TranslateC.txt", FileMode.Open, FileAccess.Read)
        sr = New StreamReader(fs)

        count = 0
        Do While sr.Peek() >= 0
            Dim read = sr.ReadLine()

            If read <> Nothing Then
            Dim words As String() = read.Split(",")
            TranslateWords(count) = New String() {words(0), words(1), words(2)}
            End If

            count = count + 1
        Loop
        sr.Close()
    End Sub

    Private Sub SortArray()

    End Sub

    Private Sub btnTranslate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnTranslate.Click
        Dim sentence As String = txtEnglish.Text
        Dim splitSentence As String() = sentence.Split(New Char() {" "c})
        Dim count As Integer

        txtTranslated.Text = ""

        If radioFrench.Checked Then

            For Each word As String In splitSentence
                Dim translated As Boolean

                translated = False
                For count = 0 To 15
                    If TranslateWords(count)(0).ToLower() = word.ToLower() Then
                        txtTranslated.Text += TranslateWords(count)(1) + " "
                        translated = True
                    End If
                Next

                If translated = False Then
                    txtTranslated.Text += word + " "
                End If

            Next

        ElseIf radioGerman.Checked Then

            For Each word As String In splitSentence
                Dim translated As Boolean

                translated = False
                For count = 0 To 15
                    If TranslateWords(count)(0).ToLower() = word.ToLower() Then
                        txtTranslated.Text += TranslateWords(count)(2) + " "
                        translated = True
                    End If
                Next

                If translated = False Then
                    txtTranslated.Text += word + " "
                End If

            Next

        Else
            MsgBox("You must select French or German before trying to translate", MsgBoxStyle.Information)
        End If

    End Sub
End Class

Luc Pattyn5-Jul-09 12:40

Luc Pattyn

5-Jul-09 12:40

Hi,

I don't know what happened here, you started explaining a nice structure (Translate) holding three strings, one for each language; later on I don't see that structure used anywhere, instead a lot of code I did not understand at first glance, anyway too much to get the required things done.

Collection classes have Sort methods: Array has a static Sort, most Lists and Dictionaries have an instance Sort() method; they all take an optional IComparer<Translate>, and that is what you need: a Compare method that understands your structure, takes the right language string, and compares two of them.

For three languages, that would mean three comparers, each of them holding some 5 lines of code (which I am not venturing to write down here as my Basic isn't very fluent, and some has to be left for you too).

BTW: I don't like your structure''s name, a structure holds data, so it is (almost) an object, don't call it a verb then. Maybe MultilingualTerm would fit.

Smile | :)

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Jacob Dixon5-Jul-09 12:44

5-Jul-09 12:44

I see what you are saying. The top of my question was basically what I was trying to do. Towards the bottom of my post is what I have written that actually works, but wasn't using a Array Structure and sorting it like the project requested. I'll have ot look up more on the IComparer.

Gideon Engelberth5-Jul-09 12:44

Gideon Engelberth

5-Jul-09 12:44

I think you should look to use the overload of Array.Sort that takes an IComparer(Of T)

The comparer would look something like this (WARNING: code typed directly into the reply)

Friend Class TranslationSorter
  Implements IComparer(Of Translate)

  Public Function Compare(ByVal x as Translate, ByVal y as Translate) as Integer
    'you will need null checks here to decide how to sort in nulls

    'this will use the default sort order for strings
    Return x.English.CompareTo(y.English)
  End Function
End Class

Array.Sort(yourArray, New TranslationSorter)

With this approach, you could add a language property to the TranslationSorter class to make it do other languages.

On an unrelated note, StreamReader has an EndOfStream property instead of needing to do .Peek() >= 0

Jacob Dixon5-Jul-09 13:52

5-Jul-09 13:52

I actually found what my professor was wanting. I wasn't aware that she posted the code. She used a bubble sort for the structure array:

Private Sub bubbleSort(ByRef arrayName() As Words)
    Dim temp As Words

    Dim numItems As Integer = arrayName.GetUpperBound(0)  ' number of items in array

    For passNum = 1 To numItems - 1    ' Number of passes is 1 less than number of items in array
        For i As Integer = 1 To (numItems - passNum) ' Each pass needs 1 less comparison
            If (arrayName(i - 1).English > arrayName(i).English) Then
                temp = arrayName(i - 1)
                arrayName(i - 1) = arrayName(i)
                arrayName(i) = temp
            End If
        Next
    Next
End Sub

Gideon Engelberth5-Jul-09 15:56

Gideon Engelberth

5-Jul-09 15:56

FYI, you do not need to pass the array ByRef to the function. Passing the array ByVal will still allow you to sort the array and have the effects noticed in the original function. Passing an array ByRef would only be useful if you were going to replace the entire array with another array. For example, if you were somehow trimming the array in a function, you would need to pass ByRef.

I'm assuming that the bubble sort was part of the assignment, but otherwise would still recommend using Array.Sort

Jacob Dixon5-Jul-09 15:59

5-Jul-09 15:59

Interesting... well the bubble sort is not part of the assignment. She just gave us that. It just says to "Sort" it. To be honest.. I'll have to read more on the IComparer because I don't fully understand it.

Luc Pattyn6-Jul-09 0:46

Luc Pattyn

6-Jul-09 0:46

Hi,

a class implementing IComparer basically says Ï have a method Compare() that knows what the relative order would be of two objects of a given type; it will return zero when order is irrelevant (i.e. both objects are equal), a negative value if object1 should preceed object2, and a non-zero positive one if object1 should follow objects2."

So basically an integer Compare() method could just return the difference of both numbers; and a simple string compare method is obviously available in the string class.

Smile | :)

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Drag&Drop problem

The real $M@5-Jul-09 0:17

The real $M@

5-Jul-09 0:17

Hi I'm writing a program that has a ListBox control. If the user drags a file and drops it on the listbox, the filename should be added to the list. I'm using the following code:

Private Sub ListBox1_DragEnter(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles ListBox1.DragEnter
   If e.Data.GetDataPresent(DataFormats.FileDrop) Then
      e.Effect = DragDropEffects.Copy
   Else
      e.Effect = DragDropEffects.None
   End If
End Sub

Private Sub ListBox1_DragDrop(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles ListBox1.DragDrop
   Stop 'This is called
   Dim s$ = e.Data.GetData(DataFormats.FileDrop, True) 'Why does this exit the sub?
   Stop 'This not
   '...
End Sub

As you can see, I put 2 stop statements in the DragDrop event. The first of them is called and stops debugging, but then e.data.getdata somehow exits the sub, and so nothing happens.
Is it even possible that a procedure exits the sub it is called from (without exiting the thread)???

I'm very confused Confused | :confused:

; I would be grateful to anyone who could give me an explanation for this.

Mycroft Holmes5-Jul-09 2:14

Mycroft Holmes

5-Jul-09 2:14

What on earth is a stop statement - never used one never even heard of one.

Why not just use a breakpoint and inspect the content of e.

Never underestimate the power of human stupidity
RAH

Henry Minute5-Jul-09 4:18

Henry Minute

5-Jul-09 4:18

I'm glad you made that reply. I was going to say exactly the same, but as I do not do much VB it might have passed me by and I didn't want to appear dumb. $Shucks | :-\$

Henry Minute

Do not read medical books! You could die of a misprint. - Mark Twain
Girl: (staring) "Why do you need an icy cucumber?"
“I want to report a fraud. The government is lying to us all.”

Mycroft Holmes5-Jul-09 14:10

Mycroft Holmes

5-Jul-09 14:10

Yeah, just got into the office and about to fire up VB/MSDN to find out what. I used VB since the early 90's (I now use C#) and have never used a stop statement.

Never underestimate the power of human stupidity
RAH

Alan N5-Jul-09 4:05

Alan N

5-Jul-09 4:05

Hi,
The FileDrop data format is a StringCollection so there should be a runtime error when you try to assign into the string s$.

The question is why do you not see the exception?
Do you have ON ERROR GOTO 0 anywhere in your code?

Alan.