We will learn a great deal about inheritance in the next section, but here is a pretty picture that shows how private, protected, and public keyword usage on properties and methods helps you control their access across classes.

In the previous figure, Class A defines three properties a, b, and c, which are private, public, and protected, respectively. Class B, which is a subclass of A, may freely access and modify the public and protected variables of Class A as if it were its own, though it may not access Class A's private properties. Class C, which is a not related to Class A or B, may only access A's or B's public properties. Note that the inherited public properties, such as A may be accessed via an instance of B even though it is defined in A. This is because of the subclass definition that B inherits all public and protected of its parent class. These access rules apply exactly the same way for methods as it does for properties.