Nested loops problem

**Symplystyc** · 06-23-2011, 05:35 PM

This is my first attempt at using vba. What I'm trying to do is find palindromes that are multiples of three digit numbers. I figured I'd start with 100 and multiply that by 100-999 then jump to 101 times 100-999 and so on untill 999-999 and excel check each number to see if its a palindrome.

I know my code is ugly but here it is.

Sub Test2()
    x = 100
    y = 100
    
    Do While x < 1000

'Starts off with x = 100   

    A = x * y

'multiplies x times y

    b = Str(A)
    c = StrReverse(A)

'converts A to a string and its reverse
'then compares the two strings  

        If StrComp(b, c, vbTextCompare) = 0 Then
        MsgBox b

'tells me if its a palindrome

        Else
        End If
        
       
        
'Heres my problem the code goes through this loop   
'but never repeats it, y goes to 1000 and stays there.     
        Do While y < 1000
        y = y + 1
        A = x * y
        b = Str(A)
        c = StrReverse(A)
       
        If StrComp(b, c, vbTextCompare) = 0 Then
        MsgBox b
        Else
        End If
       
        Loop
    
    
    x = x + 1

'adds one to x and starts loop over

    Loop
    
End Sub

I've added some comments but they most likely make the code hard to read.
While testing this out I tossed in message boxes to see what wasnt working and it appears the my second loop only happens once.

What I dont want is a solution to how to find the palindromes, what I would like would be if someone could explain why my second loop isnt restarting.

**shg** · 06-23-2011, 05:49 PM

How about ...

Sub Test3()
    Dim i           As Long
    Dim j           As Long
    Dim ij          As Long

    For i = 100 To 999
        For j = i To 999
            ij = i * j
            If CStr(ij) = StrReverse(CStr(ij)) Then
                Cells(Rows.Count, "A").End(xlUp).Offset(1).Resize(, 3).Value = Array(i, j, ij)
            End If
        Next j
    Next i
End Sub

**barryleajo** · 06-23-2011, 05:58 PM

Hi Symplystyc
It looks like your y-loop is executing properly
Try using the Debug statement as follows and watch the Immediate window

Do While y < 1000
     Debug.Print y
etc.

Need some attention to your logic?

**Symplystyc** · 06-23-2011, 06:25 PM

Barryleajo, I put in Debug.Print y and nothing happened. any suggestions.

and thanks shg I didnt even consider using For statements. but now I want to figure out what I did wrong with the Do statements.

**barryleajo** · 06-24-2011, 02:24 AM

Hi Symplystyc
Have you got your Immediate window in view?
In the VBE editor, open it from the View menu.
It will likely dock as a window at the bottom of the code window.
This is the only place that you will see anything "happen".
It should (does in my test) report the value of y each time it iterates the loop