some VB code help.....?

[jamshid]

hi

In my program i want to search through the file to check to see the number
which user enter, does not exist in the file already and also to keep track of saved numbers in the file, can anyone give me some code to meet these things?

thanks.

[Electroman]

First of all are you gona be creating the file or does the file already exist?
Secondly are all numbers going to be less than 10 ie 0-9 cos this way one character can be used for each letter. Or if you want to be able to do 0-255 you could then uses the ascii code for each character as the number. If the range you want is bigger then you'll have to come up with an idea for what will be between each number to seperate them.

Either way I suggest you open the file as follows:

Open FileName For Random As #1 Len=1

This way to get data from a certain position in the file use:

Get #1, Pos, Letter

Where Letter is should be a Byte type, it will be given the ascii code for the character.
To Change/Add a number use this:

Put #1, Pos, NewLetter

Once again NewLetter is abyte that will be the ascii code for the character.

Notice that if your using the range 0-255 you can ignore the stuff about it being a ascii code and treat it as the number.

[PaulLewis]

An option if your file is simply a list of numbers (one number to a line in the file). This code will help you as a starting point. The code doesn't care what the list contains. It looks at each line at a time and compares it to your target.

I think the best thing for you to learn here are the file opening and file stepping code. The EOF() function is very important especially in sequential (ASCII) files.

Regards

Option Explicit

Private Sub Command1_Click()
  Dim result As Long
  result = FindLineInFile("123", "c:\somefile.txt")
  If result = 0 Then
    ' this means line was not found or there was an error opening the file.
    MsgBox "not found"
  Else
    MsgBox "found at line number " & CStr(result)
  End If
End Sub

Private Function FindLineInFile(sLinetoFind As String, sFileName As String) As Long
  
  Dim lLine As Long       'line number found at
  Dim f As Long           'filehandle
  Dim bFound As Boolean   'flag set when line is found
  Dim sLine As String     ' current line read from file
  
  f = FreeFile
  bFound = False
  
  On Error GoTo err_FindLineInFile  ' if the file does not exist
                                    ' then the open command will fail
  Open sFileName For Input As #f
  
  While Not bFound And Not EOF(f)
    Line Input #f, sLine
    lLine = lLine = 1     ' increment the line count
    If sLine = sLinetoFind Then
      bFound = True
    End If
  Wend
  FindLineInFile = lLine
  
err_FindLineInFile:
  On Error Resume Next    ' reset the error handler
  Close #f                ' close the file - may generate an error if it was
                          ' never opened, but the error handler will prevent a crash
End Function