Error in writing function file

I have a program ,need to create function file for it,i get error wen i create a function file

    path='D:\dataset\'

    files=dir(strcat(path,'*.jpg'));
    for k=1:numel(files)%numel(files)
      file_name=files(k).name;
      image_name=strcat(path,file_name);
    I=imread(image_name);
    I=imresize(I,[256 256]);
    size(I)
    m = mean(I(:));
    I1=double(I);
    V = var(double(I(:)));
    J = stdfilt(I); 
    SD =  std(double(I(:)));

    result=[m V SD];
    final_col2{k}=result;
    end
    save('final_col_new','final_col2');

i wrote function file as 

function k=colour1(I) 

    size(I)
    m = mean(I(:));
    I1=double(I);
    V = var(double(I(:)));
    J = stdfilt(I); 
    SD =  std(double(I(:)));

    result=[m V SD];
    final_col2{k}=result;
    end

Undefined function or variable "k".

Error in ==> colour1 at 13
final_col2{k}=result;

Error in ==> new1 at 11
colour1(I)

please help

Answer 1

[C.J. Harris]

Your function specifies 'k' as an output, yet within the function you use it as an input. There set 'k' as an input in addition to 'I'. Also, you need to determine what the output from your function is - is it 'final_col2'?

[FIR]

s it is final_col2'