saving fileXXX.bmp

i want to save bitmap (when using editor) but i dont wannt
to pen a dialog for saving ui just wana do quicksave but not replace
the file already exist so i want to maybe use such scheme i will sawe
"painting001.bmp" and if there is such number i will just increase
the number to 002 if such exist i will use 003 and so on
do yu thing it is standable to use c std lib (and probably just
fopen fclose to detect if that file already exist of there is a need
to use some specific windows functions?
i never used it though - though maybe i could becouse code
that is able to walk on directories and read all files may be handy
for various practical usage (liek finding something , removing duplicates etc)