Creating an ASCII file - blank txt file

Hello, I am trying to create an ASCII file containing a DATE column. I managed to get the code, but the txt file I am getting is not showing the dates. I can't figure out what am I doing wrong ! any help would be highly appreciated ! I have attached the data file and the txt file I am getting, and following is my code:

[DATE]=importfile('Air_Density.csv');
  DateStrings = {'01-07';'02-07';'03-07';'04-07';'05-07';'06-07';'07-07';'08-07';'09-07';'10-07';'11-07';'12-07';'13-07';'14-07';'15-07';'16-07';'17-07';'18-07';'19-07';'20-07';'21-07';'22-07';'23-07';'24-07';'25-07';'26-07';'27-07';'28-07';'29-07';'30-07';'31-07'};
  %t = datetime(DateStrings,'InputFormat',infmt)
  d=datetime(DateStrings,'InputFormat','dd-MM');
  FID=fopen('filename.txt','w');
  fprintf(FID,'%6s \n','DATE');
  fprintf(FID,'%6s \n',d);
  fclose(FID);

[Walter Roberson]

fprintf(FID,'%6s \n','DATE'); requests to print the literal string 'DATE'.

fprintf(FID,'%6s \n',DATE); would request to output the content of the variable DATE

[D.J]

I have just realised that I have done something wrong in my question here. I updated the data file and my code. I have edited the 2nd fprintf as you suggested, but now I am getting the error:

Error using fprintf
Function is not defined for 'datetime' inputs.
Error in Q14_1 (line 10)
  fprintf(FID,'%6s \n',d);

Answer 1

[Walter Roberson]

dc = cellstr(d);
fprintf(FID,'%6s \n', dc{:});

[D.J]

Perfect ! Thanks a lot Walter !!!