How do copy and mutableCopy apply to NSArray and NSMutableArray?

Question

What is the difference between copy and mutableCopy when used on either an NSArray or an NSMutableArray?

This is

Answer 1

-(id)copy always returns a immutable one & -(id)mutableCopy always returns a mutable object,that's it.

You have to know the return type of these copying stuff and while declaring the new object which one will be assigned the return value must be of immutable or mutable one, otherwise compiler will show you error.

The object which has been copied can not be modified using the new one,they are totally two different objects now.