This unit focuses on two design patterns: Observer and Strategy. We'll use these patterns to enable responsive security and flexible climate control in our smart home system.

1. Observer Pattern:

   • Purpose: Allows an object (observer) to watch another (subject) and get notified of changes.
   • Steps:
     • Define a Subject with registration, unregistration, and notification methods (e.g., for a SecuritySystem).
     • Implement observers that react to changes (e.g., SecurityApp, SecurityLight).

2. Strategy Pattern:

   • Purpose: Defines a family of algorithms and makes them interchangeable.
   • Steps:
     • Define a strategy interface with a method for the desired behavior (e.g., TemperatureControlStrategy for controlling temperature).
     • Implement specific strategies with concrete behavior (e.g., HeatingStrategy, CoolingStrategy).