Functions with the same inputs as outputs

I have the following problem:

Is there a way to execute a function in Matlab with the same inputs as outputs and my outputs depends on the inputs I give the function?

if true
  % code
function [a,b,c]=myfun(a,b,c)
a=b+c
b=a-c
c=a-b
end
end

Is it possible to do this without arrays? I don't define my inputs in Matlab. I get it from another software. Another way to describe this problem would be: I just need the right transformation of the same equation depending on my inputs.

Best regards,

Tabea