Swaping positions within an array vb.net - arrays

Question

I'm trying to code a program that has two sections depending on which of two buttons has been pressed.
The first section is the bit that is working, the user presses the first button labeled "unsort", this triggers a loop which displays an input box asking for a random number 8 times. These 8 numbers are stored in an array.
However it is the second section I'm struggling with; the second button is labeled sort and should output the numbers the user just entered using the first button is order, smallest to largest. I understand that a bubble sort must be used here and that a loop within a loop must also be used however it is the content of these loop that I don't understand. Since my original post I've edited the post to include some code in the loop I was previously stuck with, however it still isn't producing the desired output (all numbers in order) but is instead just outputting the numbers in a seemingly random order
The code is posted below with annotations:
Public Class BubbleSort1
Dim Bubble(8) As Integer
Dim UnsortedList As String
Dim n As Integer
Dim SortedList As String
Dim temp As String
Private Sub btnUnsort_Click(sender As Object, e As EventArgs) Handles btnUnsort.Click
n = 8 ' number off values on array
For i = 1 To n ' when i is between 1 and size of array
Bubble(i) = InputBox("Enter Number") ' User inputs a number
UnsortedList = UnsortedList & " " & Bubble(i) & vbNewLine ' number is added to the unsorted list variable
Next i
lblUnsort.Text = UnsortedList ' outputs the array
End Sub
Private Sub btnSort_Click(sender As Object, e As EventArgs) Handles btnSort.Click
For i = 1 To n - 1 ' When i is between 1 and the array size - 1 (8-1):
For j = 1 To n - 1 ' Second loop - when j is between 1 and the array size - 1 (8-1):
If Bubble(j) > Bubble(j + 1) Then ' if bubble value j is greater than value j - 1:
temp = Bubble(j)
Bubble(j) = Bubble(j + 1) ' These lines are supost to order the numbers but aren'r currently doing so
Bubble(j + 1) = temp
SortedList = SortedList & Bubble(j) & vbNewLine ' Adding the number in order to a variable
End If
Next j
Next i
lblSort.Text = SortedList ' outputting the ordered numbers
End Sub
End Class
As is pointed out in the code, the section of this code that orders the numbers is just putting them in a random order rather than actually ordering them.

Answer 1

With your updated code which now includes the swapping of array elements, you are building the string which shows the sorted array too soon: it will show the workings rather than the final result.
All you need to do is build the string once the array is in order:
Private Sub btnSort_Click(sender As Object, e As EventArgs) Handles btnSort.Click
' Bubble sort the array...
For i = 1 To n - 1 ' When i is between 1 and the array size - 1 (8-1):
For j = 1 To n - 1 ' Second loop - when j is between 1 and the array size - 1 (8-1):
If Bubble(j) > Bubble(j + 1) Then ' if bubble value j is greater than value j - 1:
temp = Bubble(j)
Bubble(j) = Bubble(j + 1)
Bubble(j + 1) = temp
End If
Next j
Next i
'lblSort.Text = String.Join(vbNewLine, Bubble.Skip(1)) ' an easy one-liner
' Create a string to show the sorted array...
SortedList = "" ' clear it out in case it was used previously
For i = 1 To n
SortedList = SortedList & Bubble(i).ToString()
If i < n Then ' only add a newline if it isn't the last element
SortedList = SortedList & vbNewLine
End If
Next
lblSort.Text = SortedList
End Sub
I put the .ToString() in there in anticipation of you explicitly converting the input strings into numbers; strictly speaking, the & operator will convert its arguments into strings but I prefer to make it obvious in the code.
As your code is, there is an implicit conversion from the input (a string of digits) into an integer (the type of the array elements). While this seems convenient, it can be a problem if VB guesses the wrong conversion for you. There is a way to tell it to let you know if the types of variables don't match: put Option Strict On as the very first line and it will even give you suggestions on what needs to be done to put it right.

Answer 2

If you want to prompt the user for the input, then you will first need to either get a numeric value using a control like a NumericUpDown or you will need to convert the String value to an Integer value using Integer.TryParse. Also, keep in mind that arrays in VB.Net have a 0 based index, so they start at 0, not at 1.
In terms of the Bubble Sort algorithm, you'll need a nested loop like you have with i and j, only your inner-nested loop (j) needs to iterate from the beginning of the array to the second to last item (0 to n-2). Inside of the nested loops, you would compare if the currently iterated value is greater than (or less than depending on which value you want to swap) than the next value. If so, then you'd just reassign the values at the currently iterated index.
Here is a console application example that I whipped up, it does not prompt the user for random values, rather it simply gets a collection of random values and then performs the Bubble Sort:
Private Function BubbleSort(ByVal values() As Integer) As Integer()
'Declare placeholder variables to use in the iterations
Dim temp As Integer
For outterIndex As Integer = 0 To values.Length - 1
For innerIndex As Integer = 0 To values.Length - 2
If values(innerIndex) > values(innerIndex + 1) Then
temp = values(innerIndex + 1)
values(innerIndex + 1) = values(innerIndex)
values(innerIndex) = temp
End If
Next
Next
Return values
End Function
Private r As New Random()
Private Function RandomNumbers(ByVal range As Integer) As Integer()
'Throw an exception if the value is less than 1
If range < 1 Then Throw New ArgumentOutOfRangeException("The range cannot be less than 1")
'Return a collection of random numbers
Return Enumerable.Range(1, range).Select(Function(i) r.Next()).ToArray()
End Function
Fiddle: Live Demo