Error using fprintf in fopen

Hi everybody,

I am getting the following error:

Error using fprintf Invalid file identifier. Use fopen to generate a valid file identifier.

Error in LATEST (line 2) fprintf(fid,' Lam Efficiency\n');

while I am ting to execute the following:

fid=fopen('latest.txt','wt'); fprintf(fid,' Lam Efficiency\n');

latest.txt is a text file that I have already created.

Please help

Answer 1

[Jos (10584)]

Always check the value of fid after a call to fopen to see if it is valid:

[fid, message] = fopen('latest.txt','wt') ;
if fid == -1,
   disp(message)
else
   fprintf ...
   fclose(fid) 
end