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I have a two classes:

  ------------                         ---------------
     X                                       Y
  ------------                         ---------------
  ------------    ------------------   ---------------
      A()                                   C()
  ------------                         ---------------

I want to inherit just these two functions from X class, where they are defined with the friend access modifier. My class will be:



Y class uses some functions of X class namely A and D. How can I model this relationship in a UML class diagram?

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up vote 1 down vote accepted

If the methods of X are instance methods, you can use the association relationship, which is a solid line between the two classes, however this might indicate to the reader of the model that the relationship is bidirectional. If an instance of Y maintains a reference to X in it and X does not maintain any kind of reference to 'Y', you can add the open-ended arrow to the end pointing toward X to add directionality. If Y can't exist without X, you can also consider using aggregation to indicate this.

If the methods of X are static, consider the dependency relationship, represented by a dotted line and open ended arrow from Y to X. This relationship is used Y calls static methods of X or if the functions of Y take X as a parameter but a reference to X is not maintained within an instance of Y.

In your specific case, when you're trying to model the friend relationship in C++, the information that I can find (such as this question on Stack Overflow) seems to suggest that you should annotate the members of X with the <> stereotype. From this point, I'd use either the association or dependency relationship discussed above, based on how Y is accessing X, with association if Y maintains an instance of X and dependency if Y receives instances of X as parameters to functions as they are needed.

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Thanks so much, one last thing which free uml tool compatible with uml 2.0 should I use ? Staruml is not so compatible with uml 2.0. Thanks again – gveaf Nov 27 '12 at 14:48
@user1796528 I can't answer that question. I'd recommend trying Eclipse's Papyrus plugin, though. It supports most of (maybe all) of UML 2.0 and most of SysML as well. – Thomas Owens Nov 27 '12 at 14:52

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