iOS Simple Question

[jlw2387]

I have been working through an iPhone development book and I ran across this bit of code:

-(IBAction)switchChanged: (id)sender {
     UISwitch *whichSwitch = (UISwitch *)sender;
...

I dont really understand the why there is a * before the ). Can someone explain this?

 

[firewood]

(UISwitch *)

tells the compiler to treat the following item as a pointer to a UISwitch object.

Why is this needed? Because:

(id)sender

doesn't tell the compiler what type of variable the name "sender" is referring to.

 

[jlw2387]

I think I understand. So even if I know what class of object will be sent to "sender", this tells the compiler what class it is. Can I access sender's class properties directly or is the only way to do it is to copy to a new object like they did in the example?