MFC, How do I check the CString format is match the IP Format

Question

MFC, How do I check the CString format is match the IP Format,

For example User input

192.168,1,1 Error format

256.256.2.2 Error format

192.168.2 Error format

Some tip tell for me, thx

Answer 1

OK, I find the solution

// precisely 3 periods (.), my ip is save if strCtrlIP
    CString strCheck(strCtrlIP);
    int nPointNum = 0;

    nPointNum = strCheck.Remove('.');

    if(nPointNum != 3)
    {
        AfxMessageBox(_T("IP example：192.168.0.1"));
        return;
    }

    // numbers between periods, 0 <= number <= 255
    strCheck.Format(_T("%s"), strCtrlIP);
    while(strCheck.Find(_T(".")) >= 0)
    {
        int nLoc = strCheck.Find(_T("."));
        int nVal = _ttoi(strCheck.Left(nLoc));
        strCheck = strCheck.Right(strCheck.GetLength() - (nLoc+1)); // egnore point

        if(nVal < nUserLimitDown || nVal > nUserLimitUp || strCheck.IsEmpty())
        {
            AfxMessageBox(_T("IP example：192.168.0.1"));
            return;
        }
    }
    if(_ttoi(strCheck) < nUserLimitDown || _ttoi(strCheck) > nUserLimitUp)
    {
        AfxMessageBox(_T("IP example：192.168.0.1"));
        return;
    }

Answer 2

Search the string, using Find(), Mid() or Tokenize() and validate it's contents, based on a few required rules:

e.g.

1. no alpha characters
2. precisely 3 periods (.)
3. numbers between periods
4. 0 <= number <= 255
5. first number > 0
6. etc...