Subfunction with output varargout returns only first element of cell array. Why?

This is my script:

 a=9;
 b=2;

 [varargout] = myfunc(a,b)

 c=varargout

 function [varargout] = myfunc(a,b)

 sum=a+b;
 dif=a-b;
 prod=a*b;

 varargout={sum,dif,prod}

 end

After execution, the value of c is 11. I want it to be an array, with values 11, 7, 18. {sum, dif,prod}. What is wrong with my script, and how can I get the desired array?

Answer 1

[Matt J]

I you only want all the computations bundled into one output argument, then varargout is not the right thing:

 function c = myfunc(a,b)

   sum=a+b;
   dif=a-b;
   prod=a*b;

   c={sum,dif,prod};

[Pal Szabo]

Thanks Matt. What happens if I want to change the number of outputs? Lets say, when I first call the function, I need sum only, then sum and dif, then sum,dif,prod? How can I do that using the same function?

[Matt J]

In that case, your original code is correct, but you need to call myfunc with more output arguments

   sum=myfunc(dif)

or

[sum,dif] = myfunc(a,b)

or

[sum,dif,prod] = myfunc(a,b)

If you want a single output array but containing variable amounts of data, you have to control that through the input arguments,

   function out = myfunc(a,b, howmany)

     sum=a+b;
     dif=a-b;
     prod=a*b;

     c={sum,diff,prod};

     out=c(1:howmany);

[Pal Szabo]

Now it works. Thank you!