a demo of observer / pub-sub pattern

how to run?

make (if make command is installed on your machine.)

then what you will see?

three observers (subscribers) receive various notifications.

Many publishers want to send events to their subscribers.
Subscribers want to subscribe various publishers
they do not need mutual communication. a publisher always sends messages and a subscriber always receives messages.

first, read main.cpp and see the program's overview.
second, read publisher.h and observer.h.
- They are just interfaces and have no corresponding implementation.
- They exist just to clarify what multiple kinds of observers shoud be able to and what multiple kinds of publishers should be able to.
  - (In this program, just only one kind of observers and one kind of publishers are implemented. But usually, the program will have many kinds of those.)
finally, read anything else.