How to return a default widget structure if not enough input arguments are passed?

function res = createWidget(typeArg, matArg, prongsArg, massArg)
if (HELP HERE)
  res.type = '';
  res.material = '';
  res.prongs = 0;
  res.mass = 0;
else
  res.type = typeArg;
  res.material = matArg;
  res.prongs = prongsArg;
  res.mass = massArg;
end

 end

How would I go about creating that empty default structure if, say, only three input arguments are passed instead of the four? Thanks!

Answer 1

[Nick]

This is easily solved using nargin: https://nl.mathworks.com/help/matlab/ref/nargin.html.

A small example

function res = createWidget(typeArg, matArg, prongsArg, massArg)
   % set default values
   res.type = '';
   res.material = '';
   res.prongs = 0;
   res.mass = 0;

    % set parameters based on number of inputs

    for ii = 1:nargin % if nargin is 0 loop gets bypassed
      switch ii
        case 1
          res.type = typeArg;
        case 2
          res.material = matArg;
        case 3
          res.prongs = prongsArg;
        case 4
          res.mass = massArg;
      end
    end
 end

[Guillaume]

You don't even need the if nargin>0 since the loop will be entirely bypassed anyway if nargin is 0.

[Nick]

You are absolutely right. I never tried to give an empty vector to a for loop before so i assumed it would give an error. I updated my answer to match your comment. Thanks