@PaulS
Hi and thanks again for the help, I have other questions:
when i compile the code line you have given to me, at: char monthNames[] = {"", "Jan", "Feb", "Mar", "Apr"}; the compiler says:
error: too many initializers for 'char []'
and for: SD.mkdir((const char )dirName); error: invalid conversion from 'const char' to 'char*'
then I don't know if there are other errors
I put this code lines in a program just to try..