Program 8.3 Square.m page 164 (156 3rd edition)

[wellaged37]

code fragment:  [self setWidth: s andHeight: s];

Is it legal to use as an alternative to this fragment, the following?

width = s; height = s;

[esc]

Yes, you have direct access to the parent/super class' instance variables.

[wellaged37]

Thanks, I thought as much.

[mdeh]

Thanks, I thought as much.

But....what you **Don't** have access to is anything else important that [setWidth: andHeight:] might also be doing. For instance, lets say that you were actually copying instead of directly assigning the variable, with your method you would
a) either have to duplicate code
b) have 2 different sets of values stored

So, as a general principle, use what you already have.

[skochan]

Yes, and also if you have synthesized accessor methods, in general you'll want to use the synthesized methods and not do direct assignment to the instance variables.

Cheers,

Steve

[wellaged37]

Thanks mdeh and steve for the additional comments. I must remember to use accessor methods and methods that I already have. As yet, I don't know anything about copying so I wait until it's discussed in the book.