Anyone good at VB?

[ThaSaltCracka]

I am currently in a VB class and I am confused to all [censored]. Curious if anyone can maybe lend a hand.

Current directions:
Define an array named data() of 30 integers. Assign integer values to the elements of data(i) with Basic statements, not be reading information from an input file. Use a symbolic constant named max for the number 30 of elements. Initialize the first 10 elements of data(i) to i*11; note that VB uses a zero-based lower bound. Initialize the next 10 elements of data(i) to –i, and set the last 10 elements of data(i) to i. When the initialization is complete, print the whole array, prefixed by the string "initial data:" and then the 30 numbers, 10 numbers per output line. Use the previously established method of first concatenating all substrings into a String object, including vbNewlines and blanks for separation.

Here's what I have so far:
Dim a(30) As Integer
Dim i, j As Integer
Dim s As String = "initial data:" & vbNewLine
Const max As Integer = 30

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim s As String = a(i) & " "
For i = 0 To 9
a(i) = -11 * i
Next
For i = 10 To 19
a(i) = -i
Next
For i = 20 To 29
a(i) = i
Next
s = s & i & " "
If i Mod 10 = 0 Then
s = s & vbNewLine
End If
MsgBox("Initial data:" & s)
End Sub


I later have to sort the values in non-descending order and print that result. I think I can do that, I am just having problems computing the values and getting them to output in a message box. Any help would be very appreciated!

[jjshabado]

I don't know the language or the syntax, but if your for loop syntax is correct you're just missing a final loop. The variable i is probably only valid between the lines

For i = ...

...

Next

So at the end you say:

s = s & i & " "
If i Mod 10 = 0 Then
s = s & vbNewLine
End If

But that isn't inside of a for loop and so the value i is meaningless. You probably want to put that inside a loop counting from 0 to 29.

[Meech]

You could do something like this for the output

s = "initial data: "
for i = 0 to 29
s = s & a(i) & " "
If (i+1) Mod 10 = 0 Then
s = s & vbNewLine
End If
next i

msgbox s


and for the first loop you could do it all in one, ala:

for i = 0 to 29
if i < 10 then a(i) = 11 * i
if i >=10 and i <=19 then a(i) = -i
if i > 19 then a(i) = i
next i

Or you could use a case statement.

[ThaSaltCracka]

thanks guys, Meech that looks like it might work!

[ThaSaltCracka]

thanks again Meech. I got everything to work right, EXCEPT the sorting. Could you possibly point me in the right direction?

[Meech]

I'm a database guy so a simple "SORT BY" or more recently a [img]/images/graemlins/blush.gif[/img]rder=> gets the job done.

But sort 101 is the bubble sort. Here is an example I nabbed off the net. If you need some help adapting it, lemme know.

' Bubble Sort

Dim I, J, IntArray(), Temp as Integer ' Declare Variables

For I = 1 To Length - 1 ' Supposed to be the smaller value
For J = I To Length ' Supposed to be the larger value
If IntArray(I) > IntArray(J) Then ' Compare Cells
Temp = IntArray(I) ' \
IntArray(I) = IntArray(J) ' | Swap Cells
IntArray(J) = Temp ' /
End If
Next
Next


http://en.wikipedia.org/wiki/Bubble_sort

[BeaucoupFish]

You were told to declare max as a constant, but you didn't use it to initialise the array:

Const max As Integer = 30
Dim a(max) As Integer

Scope: you have declared the string s globally and again locally. You should lose all the global declarations, make them all local.

Also, note that in VB at least, the following declaration makes i a variant, and j an integer
Dim i, j As Integer

Either do

Dim i As Integer, j As Integer

or better yet

Dim i As Integer
Dim j As Integer

Actually, you are not even using the second variable.
Finally, from your supplied code, I cannot imagine you are getting much output.

Why not populate your string as you loop through setting the array values? Also, please note spacing and indentation for awesome readability [img]/images/graemlins/smile.gif[/img] (only shows up using .... sorry)

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
....Const max As Integer = 30
....Dim a(max) As Integer
....Dim i As Integer
....Dim s As String

....s = "initial data:" & vbNewLine

....For i = 0 To 9
........a(i) = i * -11
........s = s & a(i) & " "
....Next

....s = s & vbNewLine

....For i = 10 To 19
........a(i) = -i
........s = s & a(i) & " "
....Next

....s = s & vbNewLine

....For i = 20 To 29
........a(i) = i
........s = s & a(i) & " "
....Next

....s = s & vbNewLine

....Call MsgBox(s)

End Sub