C / C++ / MFC

WM_CREATE:
keyFile=(L"C:\\key.txt",GENERIC_READ|GENERIC_WRITE,FILE_SHARE_READ|FILE_SHARE_WRITE,NULL,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,NULL);
            //last error here gives me 0.
            if (keyFile != INVALID_HANDLE_VALUE){               
                if (GetLastError() == ERROR_ALREADY_EXISTS){                     
                 // Read file here
                    SetFilePointer(keyFile,0,0,FILE_BEGIN);
                    ReadFile(keyFile,szKeyRead,11,&dwBytes,NULL);
                    if(lstrcmp(szKeyRead,szKeyBuffer)==0){
                        //Nothing and continue if key is correct.
                    }else{                  
                    DialogBox(hInst,MAKEINTRESOURCE(IDD_REG),hWnd,Reg);//Dialog key if key is not correct

<pre>
                }
            }else if(keyFile == INVALID_HANDLE_VALUE || keyFile==NULL|| keyFile==(HANDLE)ERROR_FILE_NOT_FOUND){
                DialogBox(hInst,MAKEINTRESOURCE(IDD_REG),hWnd,Reg);//Dialog key if any of the above

    // Ask for key and write file here
            }else{
                MessageBox(hWnd,L"Problem with Registration.\n",L"Registration",0);
            }
                 CloseHandle(keyFile);
                        }</pre>

Quote:

Now when l have the code above, the if() statements executes but lands at else if statement
which l think is wrong.

Quote:

but to my surprise, when l change it to the code below, no part of the if statements runs and lasterror gives me 2.

keyFile=CreateFile(L"C:\key.txt",GENERIC_READ|GENERIC_WRITE,FILE_SHARE_READ|FILE_SHARE_WRITE,NULL,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,NULL);

<blockquote class="quote"><div class="op">Quote:</div>

<pre>
        if(lstrcmp(szKeyBuffer,szKey)==0){  //key is user entered strings.

            keyFile=CreateFile(L"C:\key.txt",GENERIC_READ|GENERIC_WRITE,FILE_SHARE_READ|FILE_SHARE_WRITE,NULL,CREATE_NEW,FILE_ATTRIBUTE_NORMAL,NULL);//Here whenever l use \\, file does not create unless l use \. returns ALLREADY EXISTS if file exists. New if not
            if(GetLastError() == ERROR_ALREADY_EXISTS){
                MessageBox(hwnd,L"Sorry though!",L"Error",0);
                SetFilePointer(keyFile,0,0,FILE_BEGIN);
                WriteFile(keyFile,szKey,11,&dwBytes,NULL);                  
                EndDialog(hwnd,TRUE);
                }else
                    SetFilePointer(keyFile,0,0,FILE_BEGIN);
                    WriteFile(keyFile,szKey,11,&dwBytes,NULL);                                          
                    EndDialog(hwnd,TRUE);
            }else{
                PostQuitMessage(0);
                }</blockquote></pre>

fstream in("test.txt",ios::in | ios::out);
if(!in)
    cout<<"error...";
else
{
    char ch;
    in.seekg(0,ios::end);
    int end=in.tellg();//get the length

    in.seekg(0);//get back to the start
    for(int i=0;i<end;i++)
    {
       //in.seekg(in.tellg());//if i uncomment this the code will work
       if(!in.get(ch).fail())//read a character
       {
           in.seekp(static_cast<int>(in.tellg())-1);//move the pointer back to the previously read position,so i could write on it
           if(in.put(ch).fail())//write back,this also move position to the next character to be read/write
               break;//break on error
       }
    }
}