Rotated Number

[halo combat22]

I need help on a project i was assigned.

The digits 0, 1, and 8 look much the same if rotated 180 degrees on the page (turned upside down). Also, the digit 6 looks much like a 9, and vice versa, when rotated 180 degrees on the page. A multi-digit number may also look like itself when rotated on the page; for example 9966 and 10801 do, but 999 and 1234 do not.
You are to write a program to count how many numbers from a given interval look like themselves when rotated 180 degrees on the page. For example, in the interval [1..100] there are six : 1, 8, 11, 69, 88, and 96.

Your program should take as input two integers, m and n, which define the interval to be checked, 1 <= m <= n <= 32000. The output from your program is the number of rotatable numbers in the interval.

You may assume that all input is valid.
Sample Session User input is in italics.

Enter the lower bound of the interval:

1



Enter the upper bound of the interval:

100



The number of rotatable numbers is:

6

I need a way to recognize these numbers.

Any help is appreciated.

[YarrOfDoom]

Use a for-loop to loop trough the numbers n to m.
For checking a number, convert it to a string using CString(number), then use another for-loop to loop trough every character of your number.
Say we call the position in the string of the current character a. Then first check if your character is one of the special cases (if not, you can abort the whole loop and check the next number). Second, check if the character at position StringMadeOutOf Number.length-(a-1) is the character you need (eg: 1 for 1, 6 for 9, 8 for 8, 9 for 6,...), if not, abort loop and you can check the next number. If the number gets trough the whole loop then it's one of the cases where it is the same if you turn it 180°.

Yarr

[halo combat22]

Private Sub Command1_Click()
    Dim n, m, i As Integer
    Dim s As String
    m = txtm.Text
    n = txtn.Text
    For i = m To n
        For s = 1 To i - 1
   'where does cString go?
End Sub
 

Where does cString go?
If it is a vb 2005 express thing i can't use it since i use vb6.

[Killer42]

... Where does cString go?
If it is a vb 2005 express thing i can't use it since i use vb6.

I believe that is VB.Net code (something later than VB6, anyway). However, I don't think we can go into too much detail, as we have a definite policy of not answering homework/classwork assignments for you.

Suffice it to say that Cstring would (presumably) be converting a number into a string. You will need to make a real effort to solve the problem yourself. Show us what you write, and we'll see if we can help nudge you in the right direction.

See the posting guidelines.

[YarrOfDoom]

Oww wait, it's not CString(), but just Str(), I mixed up a little with CInt()...

[halo combat22]

Private Sub Command1_Click()
Dim s, sI, One, Two, Three, nCount As String
Dim m, n, nLen As Integer
Dim b As Boolean
m = Text1.Text
n = Text2.Text
For i = m To n
    sI = Str(i)
    nLen = Len(sI)
    For j = 1 To nLen
        Three = Mid(sI, nLen, 1)
        If Three = 2 Or Three = 3 Or Three = 4 Or Three = 5 Or Three = 7 Then
        b = False
        Else
        b = True
        End If
        One = Mid(sI, 1, 1)
        Two = Mid(sI, nLen, 1)
        If (b = True And One = Two) Then
            nCount = nCount + 1
        End If
 
 
 
        MsgBox (nCount)
 
    Next
Next
 
End Sub
 

Well i got this far but it still hasn't worked? What is the problem?

[YarrOfDoom]

I should use "select case" instead of "if", and you shouldn't place the msgbox inside a loop.

[Killer42]

...Well i got this far but it still hasn't worked? What is the problem?

Can you be more specific than "hasn't worked"?

Also, I think you will find it much easier if you first work out in detail the exact process you are going to use, before you try to write the code. That's where "pseudo-code" comes in very handy. For example...

For each number N in the range 1 to 100
  For Each digit of N
    If digit is 1 or 8 or 0 Then
      Blah...
    Else If digit is 6 or 9 Then
      Blah...
    Else
      Blah...
    End If
  Loop
Loop