% we must begin with this kind of syntax:
%
% function [arg1out,arg2out,...,argNout] = fileName( arg1in, arg2in, ..., argnNin)
%
% so that matlab knows we want this to be a "function" 
%
% note that when calling the function, you can capture any number of outputs
% you like, e.g.
%
% egfunc(a,b) -- does nothing unless egfunc has side-effects, such
%                as writing to disk, here it does not.
%
% c = egfunc(a,b)     -- captures first output argument only
% [c,d] = egfunc(a,b) -- captures both output arguments

function [c,d] = egfunc(a,b)

c = a + b;  % just make sure you set the output variables to something
d = a - b;