Strange behavior

[Maki 1sy8]

Hi all.

With the following function I found in the function help
function [x,y]=myfct(a,b)
x=a+b
y=a-b
endfunction

I tried
-->c=3;d=4;
-->[a, b]= myfct(c, d)
b  =

  - 1.
 a  =

    7.

Why the following ???

-->myfct
 ans  =

    6.