Head First Design Patterns used in the original book is written in JAVA code, the network also has C#, but did not see with C achievable. This is what I use C realization of the Observer Pattern code

Packet : 51622439observerpattern.rar filelist
ObserverPattern\ObserverPattern.ncb
ObserverPattern\ObserverPattern.sln
ObserverPattern\ObserverPattern.suo
ObserverPattern\ObserverPattern\ObserverPattern.vcproj
ObserverPattern\ObserverPattern\ReadMe.txt
ObserverPattern\ObserverPattern\stdafx.h
ObserverPattern\ObserverPattern\stdafx.cpp
ObserverPattern\ObserverPattern\ObserverPattern.cpp
ObserverPattern\ObserverPattern\Subject.h
ObserverPattern\ObserverPattern\Subject.cpp
ObserverPattern\ObserverPattern\Observer.h
ObserverPattern\ObserverPattern\Observer.cpp
ObserverPattern\ObserverPattern\DisplayElement.h
ObserverPattern\ObserverPattern\DisplayElement.cpp
ObserverPattern\ObserverPattern\CurrentConditionsDisplay.h
ObserverPattern\ObserverPattern\CurrentConditionsDisplay.cpp
ObserverPattern\ObserverPattern\Debug
ObserverPattern\ObserverPattern
ObserverPattern

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