Why do I need to use this.mag, why doesn't mag work?

It seems that methods of classes always need to be passed the object i.e. the first parameter needs to be this, even if it is not used. The editor complains however if you pass it this and don't use it. Annoying.

Anyway my question is, why do you sometimes need to explicitly call a function/method with this in front of it and other times not.

e.g.

function y=mag(this,x)
y=max(abs(real(x)),abs(imag(x)))+floor(min(abs(real(x)),abs(imag(x)))/4);
end

this.mag(9)

works but

mag(9)

is not recognised as a function

Michael

[Jan]

@Michael: I've formatted your code to improve th readability.