Subscript indices must either be real positive integers or logicals

hello recently I'm learning matlab. i have this problem:

j  = read(img);
u=im2bw(img);
imshow(u);

and main:

if[imgName,path] = uigetfile('*.jpg','Select the MATLAB code file');
img=imread([path imgName]);
j  =read(img );

matlab error:Subscript indices must either be real positive integers or logicals. how can I read an image by main function that using other read function?

[Stephen23]

Please edit your question and give us the complete error message. This means all of the red text. It has useful information for us.

[Guillaume]

What is read? A function that you've written?

[elena rondina]

ok error message is:

if Subscript indices must either be real positive integers or logicals.
Error in re (line 4)
j  =main(k );

read is A function that you've written.what is this error?what's the solution?

[Star Strider]

What is ‘main’?

What is the value of ‘k’?

Answer 1

[Image Analyst]

Why do you have "if" in this line:

if[imgName,path] = uigetfile('*.jpg','Select the MATLAB code file');

Try getting rid of that if, and just start with the brackets. Or better yet, try more robust code like this:

% Have user browse for a file, from a specified "starting folder."
% For convenience in browsing, set a starting folder from which to browse.
startingFolder = 'C:\Program Files\MATLAB'; % Wherever you want....
if ~exist(startingFolder, 'dir')
  % If that folder doesn't exist, just start in the current folder.
  startingFolder = pwd;
end
% Get the name of the file that the user wants to use.
defaultFileName = fullfile(startingFolder, '*.jpg');
[baseFileName, folder] = uigetfile(defaultFileName, 'Select a file');
if baseFileName == 0
  % User clicked the Cancel button.
  return;
end
fullFileName = fullfile(folder, baseFileName)

Also, read the FAQ: http://matlab.wikia.com/wiki/FAQ#How_do_I_fix_the_error_.22Subscript_indices_must_either_be_real_positive_integers_or_logicals..22.3F about that error message.