State-driven behavior using the State Design pattern

The previous pattern illustrated not only the usefulness of modeling game states, but also how a game manager class can grow in size and become unmanageable. To manage the complexity of many states and complex behaviors of states, the State pattern has been proposed in the software development community. Design patterns are general purpose software component architectures that have been tried and tested and found to be good solutions to commonly occurring software system features. The key features of the State pattern are that each state is modeled by its own class and that all states inherit (are subclassed) from a single parent state class. The states need to know about each other in order to tell the game manager to change the current state. This is a small price to pay for the division of the complexity of the overall game behaviors into separate state classes.

Note

NOTE: Many thanks to the contribution from Bryan Griffiths which has...