Once a file has been opened for writing a string can be written to the
file using the fputs function. The following example shows
how to write the string ‘Free Software is needed for Free Science’
to the file ‘free.txt’.
filename = "free.txt";
fid = fopen (filename, "w");
fputs (fid, "Free Software is needed for Free Science");
fclose (fid);
Write a string to a file with no formatting.
Return a non-negative number on success and EOF on error.
A function much similar to fputs is available for writing data
to the screen. The puts function works just like fputs
except it doesn't take a file pointer as its input.