Program 19.5. Why are some methods not declared in the class interface?

[pierre]

Page 440.

"For our address book example, you'd have to add these methods (encodeWithEncoder: and initWithCoder:) to both the AddressBook and AddressCard classes."

Therefore these methods belong respectively to the AddressBook and AddressCard classes. In program19.5 they are defined in the implementation section of the class AddressCard but not in the interface section. Is it not mandatory to declare all methods of a class in the interface section? This is obviously not the case for this example. Why?

[pierre]

I now realize that when class A overrides an inherited method, it does not have to declare this method in the class interface.
Also if a A declares that it conforms to a protocol, it does not have to declare the methods required for that protocol.

Probably this is why the encodeWithEncoder: and initWithCoder: methods not declared in the AddressBook and AddressCard class interfaces.

[skochan]

Yes, that's true for inherited methods and methods defined in a protocol: they don't need to be declared in the interface section.

Cheers,

Steve Kochan