Issues with For Loop in VB - vb.net

Question

For i = 1 To 5
If i = 0 Then
i = i + 1
ElseIf i Mod 2 = 0 Then
LabelEvens.Text = i
i = i + 1
Else
LabelOdds.Text = i
i = i + 1
End If
Next i
I'm making a program in VB where I have to use a for loop to sort between 2 numbers(loop limit 1 and 2) and find if they are even or odd, Then output the results to 2 labels. This loop makes sense to me, but for example when I put in 1 and 4 all it outputs is a 5 in the odd label. I guess my question is can anyone see the issue with my loop?

Answer 1

You don't need to add 1 to your loop variable i manually, the for loop itself does that for you behind the scenes:
For i = 1 To 5
If i Mod 2 = 0 Then
LabelEvens.Text = i
Else
LabelOdds.Text = i
End If
Next i
You'll noticed I've also removed the If i = 0 bit since i can never be zero within that loop. It ranges from one to five inclusive.
One other thing you'll need to do is to append the value to your text box. What you have at the moment is a replacement so that it'll only be set to the last value processed. Something like this should suffice:
' Initialise to empty strings '
LabelEvens.Text = ""
LabelOdds.Text = ""
' Append the values '
For i = 1 To 5
If i Mod 2 = 0 Then
LabelEvens.Text = LabelEvens.Text & "," & CStr(i)
Else
LabelOdds.Text = LabelOdds.Text & "," & CStr(i)
End If
Next i
' Remove initial comma from both '
LabelEvens.Text = Mid(LabelEvens.Text,2)
LabelOdds.Text = Mid(LabelOdds.Text,2)

Answer 2

Some issues in your code:
For i = 1 To 5
If i = 0 Then <-- 'I' will never be 0 since you start from 1
i = i + 1 <-- Don't manually increment since you are using a for
ElseIf i Mod 2 = 0 Then
LabelEvens.Text = i
i = i + 1 <-- Don't manually increment since you are using a for
Else
LabelOdds.Text = i
i = i + 1 <-- Don't manually increment since you are using a for
End If
Next i
Another issue you have is that if you have more than one odd number in the for range (say in a range of 1 to 10) you will only get the last number. What do you want to do in this case? Concatenate all odd numbers in a string or stop after the first one is found? Do you really need a FOR loop at all?

Answer 3

you can Also state
LabelEvens.Text="" 'Clear contents of the label before assigning new values
LabelOdds.Text=""
For i As Integer = 1 To 5
If i Mod 2 = 0 Then
LabelEvens.Text = LabelEvens.Text & i
Else
LabelOdds.Text = LabelOdds.Text & i
End If
Next
From Above you can replace '&' with '+' if you want the Total.