Operations can be perform on data by sending a message to the object. Y String A string is any sequence of characters enclosed between single quotes. All symbols are unique. Array An array is a data structure whose elements can be any valid object. An array literal is an indexed sequence of literals.
All variables initially are point to nil .
Nil also can be used as the return value in a method to indicate that an operation is not successful. Return nil if aPower is not positive. Otherwise, return the result. These two functions can be performed with either binary messages or keyword messages . A statement can contain an unlimited number of these binary messages.