Design Patterns in Modern C++20: Reusable Approaches for Object-Oriented Software Design

© Dmitri Nesteruk 2022

D. NesterukDesign Patterns in Modern C++20https://doi.org/10.1007/978-1-4842-7295-4_21

21. State

Dmitri Nesteruk¹  

(1)

St. Petersburg, Russia

 

I must confess: my behavior is governed by my state. If I didn’t get enough sleep, I’m going to be a bit tired. If I had a drink, I wouldn’t get behind the wheel. All of these are states and they govern my behavior: how I feel, what I can and cannot do.

I can, of course, transition from one state to another. I can go get a coffee, and this will take me from sleepy to alert (I hope!). So we can think of coffee as a trigger that causes a transition of yours truly from sleepy to just about awake. Here, let me clumsily illustrate it for you:¹

        coffee

sleepy --------> alert

So, the State ...