Removing unnecessary 0's from an array? " InvalidCastException was unhandled"

[rosleenXOXO]

I have an array with a possible of 25 numbers that can be entered into it, i need help figuring out how to take out the unnecessary zero's for the valueas i have not entered into my array.

Public Class Form1
   
  Dim mintArray() As Integer 'Declares Array without giving it a size
  Dim Array(24) As Integer
  Dim J As Integer = 0


Private Sub btnPutNumberIntoArray_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnPutNumberIntoArray.Click

        Array(J) = CInt(txtNumbers.Text)
        J = J + 1
        txtNumbers.Clear()
        txtNumbers.Focus()

    End Sub

Private Sub btnDisplayNumbersInArray_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplayNumbersInArray.Click
        Static J As Integer
        ReDim Preserve mintArray(J)
        'Gives Array a size and preserves the array values
        mintArray(J) = CInt(txtDisplayNumbers.Text)
        J = J + 1
        txtDisplayNumbers.Clear()

        'DISPLAYS THE CONTENTS OF ARRAY.
        For I = 0 To J - 1
            'Accumulates values in Textbox2 and displays these values.
            txtDisplayNumbers.Text = txtDisplayNumbers.Text & CStr(mintArray(I)) & ControlChars.NewLine
        Next
        txtDisplayNumbers.Clear()
        txtDisplayNumbers.Focus()

        For J = 0 To 24
            txtDisplayNumbers.Text = txtDisplayNumbers.Text & CStr(Array(J)) & ControlChars.NewLine
        Next
    End Sub 

End Class

I get an error at the highlighted part : " InvalidCastException was unhandled, Conversion from string "" to type 'integer' is not valid."

[Edgemeal]

That code is basically saying Convert an empty string to an Integer, Cint can't do that, if you use TryParse instead and string is empty then the value becomes zero and no more erorrs.

Instead of an Integer array a List(Of Integer) is much easier to use, just a simple example....

Public Class Form1

    Dim MyArray As New List(Of Integer)

    Private Sub btnPutNumberIntoArray_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnPutNumberIntoArray.Click
        Dim number As Integer
        Integer.TryParse(txtNumbers.Text, number)
        If number <1 Then
            MessageBox.Show("Please enter a number greater then zero.")
        Else
            MyArray.Add(number)
        End If
    End Sub

    Private Sub btnDisplayNumbersInArray_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplayNumbersInArray.Click
        txtDisplayNumbers.Clear()
        txtDisplayNumbers.Focus()

        For i As Integer = 0 To MyArray.Count - 1
            txtDisplayNumbers.Text &= MyArray(i).ToString & Environment.NewLine
        Next
    End Sub

End Class

If you aren't going to do any math with the values you could just use a List (Of String).

[Shaggy Hiker]

I totally agree. When you use Redim on an array, with or without the Preserve, you aren't really re-sizing the array. You are actually creating a new array of the right size, then copying the existing into the new. As you might expect, that isn't terribly efficient, though there are some means to accomplish that which make it faster than you might do on your own. If you use a List, you have the Remove and RemoveAt methods, which do exactly what they say, but the List makes much more efficient use of memory for dynamically adding and removing elements.

[rosleenXOXO]

Ok thanks you guys for the help but now the rest of my program wont work :/
I get the following Error : ArguementOutOfRangerExceptin was unhandled. Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index

 Private Sub btnDisplayLargestNumber_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplayLargestNumber.Click

        Dim Largest As Integer
        Largest = MyArray(0)
        For J = 1 To 24
            If MyArray(J) > Largest Then
                Largest = MyArray(J)
            End If
        Next
        txtDisplayNumbers.Text = CStr(Largest)

    End Sub

    Private Sub btnDisplaySmallestNumber_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplaySmallestNumber.Click

        Dim Smallest As Integer
        Smallest = MyArray(0)
        For J = 1 To 24
            If MyArray(J) < Smallest Then
                Smallest = MyArray(J)
            End If
        Next
        txtDisplayNumbers.Text = CStr(Smallest)

    End Sub
    Private Sub btnDisplayRange_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplayRange.Click

        Dim Smallest As Integer
        Dim Largest As Integer
        Smallest = MyArray(0)
        Largest = MyArray(0)
        For J = 1 To 24
            If MyArray(J) < Smallest Then
                Smallest = MyArray(J)
            ElseIf MyArray(J) > Largest Then
                Largest = MyArray(J)
            End If
        Next
        txtDisplayNumbers.Text = _
        CStr(Smallest) & " to " & CStr(Largest)

    End Sub
    Private Sub btnDisplaySumOfNumbers_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplaySumOfNumbers.Click

        Dim Sum As Integer
        For J = 0 To 24
            Sum = Sum + MyArray(J)
        Next
        txtDisplayNumbers.Text = CStr(Sum)

    End Sub


    Private Sub btnDisplayMean_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplayMean.Click
        Dim lCounter As Long
        Dim dTotal As Double
        Dim dAverage As Double

        dTotal = 0
        For lCounter = 0 To UBound(Array)
            dTotal = dTotal + MyArray(CInt(lCounter))
        Next
        dAverage = dTotal / (UBound(Array) + 1)
        txtDisplayNumbers.Text = CStr(dAverage)
    End Sub
End Class

[rosleenXOXO]

I get the same error where I've highlighted red.

[vbfbryce]

Check the value of the upper bound of MyArray before the lines where you get the error.

[rosleenXOXO]

That code is basically saying Convert an empty string to an Integer, Cint can't do that, if you use TryParse instead and string is empty then the value becomes zero and no more erorrs.

Instead of an Integer array a List(Of Integer) is much easier to use, just a simple example....

Public Class Form1

    Dim MyArray As New List(Of Integer)

    Private Sub btnPutNumberIntoArray_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnPutNumberIntoArray.Click
        Dim number As Integer
        Integer.TryParse(txtNumbers.Text, number)
        If number = 0 Then
            MessageBox.Show("Please enter a number greater then zero.")
        Else
            MyArray.Add(number)
        End If
    End Sub

    Private Sub btnDisplayNumbersInArray_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplayNumbersInArray.Click
        txtDisplayNumbers.Clear()
        txtDisplayNumbers.Focus()

        For i As Integer = 0 To MyArray.Count - 1
            txtDisplayNumbers.Text &= MyArray(i).ToString & Environment.NewLine
        Next
    End Sub

End Class

If you aren't going to do any math with the values you could just use a List (Of String).

Im marking this as resolved if you know how to fix this error can you please private message me, THANK YOU

[rosleenXOXO]

I get the following Error everywhere i have highlighted red :

ArguementOutOfRangerExceptin was unhandled. Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index

Public Class Form1

    Dim Array(24) As Integer
    Dim J As Integer = 0
    Dim MyArray As New List(Of Integer)

    Private Sub btnPutNumberIntoMyArray_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnPutNumberIntoArray.Click
        Dim number As Integer
        Integer.TryParse(txtNumbers.Text, number)
        MyArray.Add(number)

        txtNumbers.Clear()
        txtNumbers.Focus()

    End Sub

    Private Sub btnDisplayNumbersInMyArray_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplayNumbersInArray.Click
        txtDisplayNumbers.Clear()
        txtDisplayNumbers.Focus()

        For J As Integer = 0 To MyArray.Count - 1
            txtDisplayNumbers.Text &= MyArray(J).ToString & Environment.NewLine
        Next

    End Sub

Private Sub btnDisplayLargestNumber_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplayLargestNumber.Click

Dim Largest As Integer
Largest = MyArray(0)
For J = 1 To 24
If MyArray(J) > Largest Then
Largest = MyArray(J)
End If
Next
txtDisplayNumbers.Text = CStr(Largest)

End Sub

Private Sub btnDisplaySmallestNumber_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplaySmallestNumber.Click

Dim Smallest As Integer
Smallest = MyArray(0)
For J = 1 To 24
If MyArray(J) < Smallest Then
Smallest = MyArray(J)
End If
Next
txtDisplayNumbers.Text = CStr(Smallest)

End Sub

Private Sub btnDisplayRange_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplayRange.Click

Dim Smallest As Integer
Dim Largest As Integer
Smallest = MyArray(0)
Largest = MyArray(0)
For J = 1 To 24
If MyArray(J) < Smallest Then
Smallest = MyArray(J)
ElseIf MyArray(J) > Largest Then
Largest = MyArray(J)
End If
Next
txtDisplayNumbers.Text = _
CStr(Smallest) & " to " & CStr(Largest)

End Sub

Private Sub btnDisplaySumOfNumbers_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplaySumOfNumbers.Click

Dim Sum As Integer
For J = 0 To 24
Sum = Sum + MyArray(J)
Next
txtDisplayNumbers.Text = CStr(Sum)

End Sub

Private Sub btnDisplayMean_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplayMean.Click
Dim lCounter As Long
Dim dTotal As Double
Dim dAverage As Double

dTotal = 0
For lCounter = 0 To UBound(Array)
dTotal = dTotal + MyArray(CInt(lCounter))
Next
dAverage = dTotal / (UBound(Array) + 1)
txtDisplayNumbers.Text = CStr(dAverage)
End Sub
End Class

[rosleenXOXO]

Check the value of the upper bound of MyArray before the lines where you get the error.

i'm confused, how would i check the value of the upper bound?
i don't think i assigned any value to the upper bound

[Shaggy Hiker]

If you are using a List, you don't check the upper bound, you check the .Count property. You can't access an item greater than .Count - 1.

With an array, you always set the upper bound, though that is something of a legacy term. In VB6, you could set the lower and upper bounds, but in .NET all arrays start at 0, so the upper bound is effectively the array size.

What you were doing was this:

Largest = MyArray(0)
For J = 1 To 24
If MyArray(J) > Largest Then

which will only work if MyArray has at least 25 items in it, because you will access MyArray(24), which is the 25th item in the array.

[Shaggy Hiker]

Please don't double post. I answered your question in the other thread.

[rosleenXOXO]

Public Class Form1

Dim Array(24) As Integer
Dim J As Integer = 0
Dim MyArray As New List(Of Integer)


Private Sub btnPutNumberIntoMyArray_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnPutNumberIntoArray.Click
Dim number As Integer
Integer.TryParse(txtNumbers.Text, number)
MyArray.Add(number)

txtNumbers.Clear()
txtNumbers.Focus()

End Sub

Private Sub btnDisplayNumbersInMyArray_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplayNumbersInArray.Click
txtDisplayNumbers.Clear()
txtDisplayNumbers.Focus()

For J As Integer = 0 To MyArray.Count - 1
txtDisplayNumbers.Text &= MyArray(J).ToString & Environment.NewLine
Next

End Sub



Private Sub btnDisplayLargestNumber_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplayLargestNumber.Click

Dim Largest As Integer
Largest = MyArray(0)
For J = 1 To 24
[B]If MyArray(J) > Largest Then[/B]
Largest = MyArray(J)
End If
Next
txtDisplayNumbers.Text = CStr(Largest)

End Sub

Private Sub btnDisplaySmallestNumber_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplaySmallestNumber.Click

Dim Smallest As Integer
Smallest = MyArray(0)
For J = 1 To 24
If MyArray(J) < Smallest Then
Smallest = MyArray(J)
End If
Next
txtDisplayNumbers.Text = CStr(Smallest)

End Sub
Private Sub btnDisplayRange_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplayRange.Click

Dim Smallest As Integer
Dim Largest As Integer
Smallest = MyArray(0)
Largest = MyArray(0)
For J = 1 To 24
If MyArray(J) < Smallest Then
Smallest = MyArray(J)
ElseIf MyArray(J) > Largest Then
Largest = MyArray(J)
End If
Next
txtDisplayNumbers.Text = _
CStr(Smallest) & " to " & CStr(Largest)

End Sub
Private Sub btnDisplaySumOfNumbers_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplaySumOfNumbers.Click

Dim Sum As Integer
For J = 0 To 24
Sum = Sum + MyArray(J)
Next
txtDisplayNumbers.Text = CStr(Sum)

End Sub


Private Sub btnDisplayMean_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplayMean.Click
Dim lCounter As Long
Dim dTotal As Double
Dim dAverage As Double

dTotal = 0
For lCounter = 0 To UBound(Array)
dTotal = dTotal + MyArray(CInt(lCounter))
Next
dAverage = dTotal / (UBound(Array) + 1)
txtDisplayNumbers.Text = CStr(dAverage)
End Sub
End Class

This is my full code, could you please tell me what i am doing wrong?

[i00]

replace this bit:

'DISPLAYS THE CONTENTS OF ARRAY.
 For I = 0 To J - 1
 'Accumulates values in Textbox2 and displays these values.
 txtDisplayNumbers.Text = txtDisplayNumbers.Text & CStr(mintArray(I)) & ControlChars.NewLine
 Next
 txtDisplayNumbers.Clear()
 txtDisplayNumbers.Focus()
 
 For J = 0 To 24
 txtDisplayNumbers.Text = txtDisplayNumbers.Text & CStr(Array(J)) & ControlChars.NewLine
 Next
 End Sub

with:

txtDisplayNumbers.text = join((from xItem in mintArray where xItem <> 0 select xItem.tostring).toarray, Environment.NewLine)

Kris

[rosleenXOXO]

Two different questions, my last question was marked resolved.

[rosleenXOXO]

I get this error ;Range variable name cannot match the name of a member of the 'object' class.



Private Sub btnDisplayNumbersInArray_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplayNumbersInArray.Click
Static J As Integer
ReDim Preserve Array(J)

txtNumbers.Text = CStr(Array(J))
J = J + 1
txtDisplayNumbers.Clear()
txtDisplayNumbers.Text = Join((From xItem In Array Where xItem <> 0 Select xItem.ToString).ToArray, Environment.NewLine)


End Sub

[rosleenXOXO]

Could you just tell me how i could insert Code2 into code1 correctly?
Code1:

Option Strict On

Public Class Form1

Dim Array(4) As Integer
Dim J As Integer = 0



Private Sub btnPutNumberIntoMyArray_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnPutNumberIntoArray.Click
Array(J) = CInt(txtNumbers.Text)
J = J + 1
txtNumbers.Clear()
txtNumbers.Focus()

End Sub


Private Sub btnDisplayNumbersInArray_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplayNumbersInArray.Click
txtDisplayNumbers.Clear()
txtDisplayNumbers.Focus()

For J As Integer = 0 To Array.Count - 1
txtDisplayNumbers.Text &= Array(J).ToString & Environment.NewLine
Next

End Sub
Private Sub btnDisplayLargestNumber_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplayLargestNumber.Click

Dim Largest As Integer
Largest = Array(0)
For J = 1 To 4
If Array(J) > Largest Then
Largest = Array(J)
End If
Next
txtDisplayNumbers.Text = CStr(Largest)

End Sub

Private Sub btnDisplaySmallestNumber_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplaySmallestNumber.Click

Dim Smallest As Integer
Smallest = Array(0)
For J = 1 To 4
If Array(J) < Smallest Then
Smallest = Array(J)
End If
Next
txtDisplayNumbers.Text = CStr(Smallest)

End Sub
Private Sub btnDisplayRange_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplayRange.Click

Dim Smallest As Integer
Dim Largest As Integer
Smallest = Array(0)
Largest = Array(0)
For J = 1 To 4
If Array(J) < Smallest Then
Smallest = Array(J)
ElseIf Array(J) > Largest Then
Largest = Array(J)
End If
Next
txtDisplayNumbers.Text = _
CStr(Smallest) & " to " & CStr(Largest)

End Sub
Private Sub btnDisplaySumOfNumbers_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplaySumOfNumbers.Click

Dim Sum As Integer
For J = 0 To 4
Sum = Sum + Array(J)
Next
txtDisplayNumbers.Text = CStr(Sum)

End Sub


Private Sub btnDisplayMean_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplayMean.Click
Dim lCounter As Long
Dim dTotal As Double
Dim dAverage As Double

dTotal = 0
For lCounter = 0 To UBound(Array)
dTotal = dTotal + Array(CInt(lCounter))
Next
dAverage = dTotal / (UBound(Array) + 1)
txtDisplayNumbers.Text = CStr(dAverage)
End Sub

Private Sub btnBinarySearch_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnBinarySearch.Click
Dim Key As Integer
Dim Low As Integer
Dim High As Integer
Dim Mid As Integer




Key = CInt(txtBinaryKey.Text)
Low = 0
High = 4

While Low <= High
Mid = (High + Low) \ 2
If Key = Array(Mid) Then
lblBinarySearchLocation.BackColor = Color.Silver
lblBinarySearch.Text = "Search Key found"
lblBinarySearchLocation.Text = "Array(" & Str(Mid) & ")"

Low = High + 1

ElseIf Key < Array(Mid) Then
High = Mid - 1
ElseIf Key > Array(Mid) Then
Low = Mid + 1
End If
End While

If Key <> Array(Mid) Then
lblBinarySearch.Text = "Search Key not found."
lblBinarySearchLocation.BackColor = Color.Red
lblBinarySearchLocation.Text = ""
End If

End Sub


End Class

*******CODE2:********

‘TOPIC: USEFUL CODE FOR CONTROLLING UNNECESSARY ZEROS IN ARRAY.
‘THERE ARE SEVERAL WAYS TO CONTROL UNNECESSARY ZEROS. THIS IS JUST ONE.
Public Class Form1

Dim mintArray() As Integer 'Declares Array without giving it a size
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) _
Handles Button1.Click
Static J As Integer
ReDim Preserve mintArray(J)
'Gives Array a size and preserves the array values
mintArray(J) = CInt(TextBox1.Text)
J=J+1
TextBox2.Clear()

'DISPLAYS THE CONTENTS OF ARRAY.
For I = 0 To J - 1
'Accumulates values in Textbox2 and displays these values.
TextBox2.Text = TextBox2.Text & CStr(mintArray(I)) & ControlChars.NewLine
Next
TextBox1.Clear()
TextBox1.Focus()
End Sub

basically how would would i add code2 into code1 one so i can get rid of the unnecessary zeros produced from not entering 25 elements, i would really appreciate it if you could hep me this.

[Shaggy Hiker]

I thought we covered that when we said: Use a List rather than an array. Perhaps it wasn't you, but using an array with Redim Preserve is a pretty ineffiicient solution. The List (of T) was introduced, in part, to provide a vastly superior dynamically sized collection.

[Shaggy Hiker]

If this is for basic class work, and you turn in a LINQ statement, that probably won't go over so well.

The problem with your loops is that you have made an array with 24 elements. Arrays all start at 0, so the elements are 0-23, not 1-24. You then loop from 1 to 24, which means that the loop will ignore array element 0, which is the first element, and will try to access array element 24, which is the 25th element, and which doesn't exist. Loop from 0 to 23 and all will be well.

[rosleenXOXO]

This is an assignment, I HAVE to do it the way my professor has asked and i must use arrays...

[Shaggy Hiker]

Classes can sure suck some times.

So, how do you mean to insert code 2 into code 1? Both of them appear to be a series of methods. In the first snippet, there would be no reason to remove empties from the sum (they make no difference), nor do you really need to remove them from the mean (you'd just leave them out when counting the number of elements). Do you need to remove them for the binary search? That doesn't seem necessary, since the array would be sorted, and it wouldn't really matter whether there were some 0s in the array.

[rosleenXOXO]

so basically the professor has given us the code2 which we are supposed to implement into the code1 (which the students have to write). code2 is supposed to remove the unnecessary 0's in the array. Im guessing that code2 has to be written into :

Private Sub btnDisplayNumbersInArray_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplayNumbersInArray.Click
txtDisplayNumbers.Clear()
txtDisplayNumbers.Focus()

For J As Integer = 0 To Array.Count - 1
txtDisplayNumbers.Text &= Array(J).ToString & Environment.NewLine
Next

End Sub

Because this is the only button that shows the number the user enters i just cant figure out how to make it work all together...my whole code works except for the extra zeros...

[rosleenXOXO]

there cant be any 0's in the Array, they numbers entered must be larger or equal to 1....and say that i only enter 12 numbers and then the 13(25 in total) other elements pop-up as zeros when i run the method above...

[Hack]

Please don't double post. I answered your question in the other thread.

Actually you answered the question in this thread as both have now been merged.

One question, one thread please.

Also, if you are going to post lengthy pieces of code please do everyone a favor
and use [code]your code goes in here[/code] tags .

Thanks.