problem with the function "fread"

i have to read a .txt file , given by my professor, and i wrote the following code

fid=fopen('shannon_odd.txt','r'); %open file
x=fread(fid,'*char'); %read file chars
binary = dec2bin(x,8); %char->binary
binary_t=transpose(binary);
binf=binary_t(:)-'0'; %vector of binary bits of file
binf=binf.';

and when i run the program, this error came at command window:

[Ive J]

Is your text file within current working directory?

[Antonis Koutsis]

it was the first thing that i had checked before i post this

Answer 1

[Jeremy Hughes]

The error indicates that fopen returned an invalid file ID.

Try this:

[fid,msg] = fopen(filename)
if fid < 0
    error(msg)
end

More than likely, the file is not in the current working directory. try

which('shannon_odd.txt')

That will show you if the file is being found, if it doesn't give a result, you'll need to provide the full path to the file.

HTH