Read m file with fgets / fgetl

Hi,

I want to read a m file called 'File1.m' and write in the same time a 'File2.m'.

My code (simplified for example) is :

Fin = fopen('File1.m','r');
Fout = fopen('File2.m','w');

while feof(Fin) == 0
     line = fgets(Fin);
     if regexp(line,'text')
        fprintf(Fout,' modified text ');
     else
        fprintf(Fout,line);
     end
end

It works perfectly EXCEPT that fgets is not reading comments in File1 (comments indicated with '%').

Do you know a way to read them? It is actually important comments.

Thanks, Clément

[dpb]

Don't think your diagnosis of your symptom is correct...there's no reason to think fgets will not read a line from a file whatever the character. Note your output is going to be all on one line as fgets strips the \n; maybe it's a display issue...

[Clément P]

I think that fgets takes into account the '\n', but fgetl does not. Maybe it is another symptom, but I don't understand why everything is write perfectly except comments. Or maybe it comes from sprintf?

edit : I checked, fgets reads all characters, including comments. I think it comes from fprintf , as the '%' is used to print variables. Do you have an idea how to overpass this?

[Clément P]

Actually it works with fwrite ;)

Answer 1

[Stephen23]

Solution Use fgetl and this:

fprintf(Fout,'%s\n',line);

Explanation there is a very large difference between these:

fprintf(fid,'%s\n',text) % correct
fprintf(fid,text) % what you are doing

because of how escaped characters get handled. Characters that need escaping include %, so when you provide it simply (as you are doing) it does not get interpreted as a simple character, but instead is a special active character. The first line shows the correct solution for your task, with a format string and your text as an argument. Read the fprintf docs for more info on this, or this excellent explanation:

http://www.mathworks.com/help/matlab/matlab_prog/formatting-strings.html

[Clément P]

Thanks a lot for the explanations :D