or how to manage access to your classes.

In PHP there are three levels of access for properties and methods from within a class: public, private, and protected.

Public access is the default setting for method and for properties.

• Public properties and methods can be accessed from any context.
• Private methods and properties can ONLY be accessed from within the enclosing class. Thesubclasses have no access to them.
• Protected methods and properties can be accessed from within the enclosing class and fromsubclasses.

According with Zend Coding Standards, variables that are declared with the “private” or “protected” modifier, the first character of the variable name must be a single underscore.

eg: private $_myVar;