Hi all, I was taking a close look at the event/track example in $ROOTSYS/test and started to wonder why a global *gTracks is defined. The constructor of the event class creates the gTracks global (a TClonesArray) if it does not exist yet and puts the fTracks datamember of the instantiated Event object to this global. In the MainEvent program only one instantiation of Event is made. In a loop the datamembers are set to different values and everytime a tree is filled with the event. I wonder now what would happen if we would create 2 Event objects. In that case both Event objects will use the same Track array. This doesn't seem object-oriented to me, and I don't see the advantage of using the global gTracks in this case. I'm a new user of ROOT so I might make a mistake here, and miss the reason why a global object should be used in this case. If this is the case I would appriciate anybody explaining this to me, so that i can use this in my own programs. (I can imagine that it has something to do with the addresspointer used by the tree fill function...) Rutger van der Eijk
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