Cocoa Fundamentals Guide: Table

**Table 2-4** Derived methods and their possible implementations
Derived Method	Possible Implementation
`lastObject`	Find the last object by sending the array object this message: `[self objectAtIndex: ([self count] –1)]`.
`containsObject:`	Find an object by repeatedly sending the array object an `objectAtIndex:` message, each time incrementing the index until all objects in the array have been tested.