Chapter 15 in brief


NSArray: An instance of NSArray holds a list of pointers to other objects.
NSArray & two methods: NSArray has two methods: 1- count: returns the number of items in an array 2- objectAtIndex: returns the pointer that the array has stored at the index specified by the argument. Please note that you can access an item in the array by its index.
Note1: This is a good idea to use fast enumeration when you want to iterate.
NSMutableArray: Arrays come in two flavors: 1- An instance of NSArray is created with a list of pointers. You can never add or remove a pointer from that array. 2- An instance of NSMutableArray is similar to an instance of NSArray, but you can add and remove pointers.