Window OnPaint function

void OnPaint(HWND hWnd,WPARAM wParam,LPARAM lParam, HDC hDC, PAINTSTRUCT* ps)
{
    HDC hDCDoubleBuffer = CreateCompatibleDC(GetDC(hWnd));
    BITMAPINFO k;
    BITMAPINFOHEADER bitmapInfo;
    bitmapInfo.biSize           = sizeof(BITMAPINFOHEADER);
    bitmapInfo.biWidth          = 150;
    bitmapInfo.biHeight         = 150;
    bitmapInfo.biPlanes         = 1;
    bitmapInfo.biBitCount       = 24;
    bitmapInfo.biCompression    = BI_RGB;
    bitmapInfo.biSizeImage      = 0;
    bitmapInfo.biXPelsPerMeter  = 0;
    bitmapInfo.biYPelsPerMeter  = 0;
    bitmapInfo.biClrUsed        = 0;
    bitmapInfo.biClrImportant   = 0;
    k.bmiHeader = bitmapInfo;
    HBITMAP bmp2= (HBITMAP)CreateCompatibleBitmap(GetDC(hWnd),bitmapInfo.biWidth,bitmapInfo.biHeight);
    HBITMAP oldBitmap;
    unsigned char a[1000000];
    unsigned char* data = a;
    int i,j,index,width,height;
    width = bitmapInfo.biWidth;
    height = bitmapInfo.biHeight;
    for(i = 0; i < height; i++)
    {
        for(j = 0; j < width; j++)
        {
            index = (width * i + j) * 3;
            data[index]       = 255;  //blue
            data[index + 1]   = 0;    //green
            data[index + 2]   = 0;    //red
        }
    }
    SetDIBits(hDCDoubleBuffer,bmp2,0, height, a, (BITMAPINFO*)&bitmapInfo, DIB_RGB_COLORS);
    oldBitmap = (HBITMAP)SelectObject(hDCDoubleBuffer,bmp2);
    BitBlt(hDC, 10, 10, bitmapInfo.biWidth, bitmapInfo.biHeight, hDCDoubleBuffer, 0, 0, SRCCOPY);
    SelectObject(hDCDoubleBuffer,oldBitmap);
    DeleteObject(bmp2);
    DeleteObject(oldBitmap);
    DeleteDC(hDCDoubleBuffer);
}