Keep getting "Undefined variable" message

tesseract72

Matlab keeps telling me that 'form' is undefined. I've included the primary function (form_letter) and the first subfunction (read_form, which is where 'form' is supposed to get defined). When I test read_form individually, 'form' gets defined and everything works, so the problem must be in the primary function, but I have no idea what it is. If it helps, in the editor window the mouseover text tells me that "the value assigned to variable 'form' might be unused."

I appreciate any help you can offer.

[php]
function [] = form_letter()

clear;
clc;

form = read_form();
structure = read_tag_sub();
result = replace_tags(structure);
output_letter(result)

end



function form = read_form()

form = '';

fid = fopen('form.txt', 'r');
if fid == -1
disp ('Could not open form.txt\n');
else
while feof(fid) == 0
%read in the string including newline one line at a time
a_line = fgets(fid);
%concatenate the line to the form
form = [form, a_line];
end
end

close_result = fclose(fid);
if close_result ~= 0
disp ('Could not close form.txt');
end

end
[/php]

shwaip

on what line do you get the error?

also, before you run your function, type

dbstop if error

to have matlab drop into the debugger, rather than just error out. it should help you debug.

tesseract72

I tried debugging using dbstop as you suggested, but it hasn't led me to figure out what's wrong.

As I probably should have mentioned, the error occurs at line 6, right at the beginning of the primary function --> form = read_form(). It tells me that form doesn't get defined.

Any ideas?

tesseract72

Never mind, figured it out.