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At this point we have our classes, our attributes,
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what we're missing is the operations for the class.
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Let me remind you that operations represent the behavior
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of a class, and that they may be found by
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examining interactions among entities in the description of my
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system. So once more, let's bring back our description, and
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let's in this case focus on this specific item.
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That says that the students may use the system to
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add courses. So this is clearly indicating an action
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that the students should be able to perform. But notice
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that this doesn't mean that this is an operation that
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should be provided by the student's class. It rather means
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that there should be, somewhere in the system, the possibility
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of performing this operation. So let's see what this means
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for our example. This might mean, for example, if we
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focus on the RegistrationManager, so that there should be an
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operation in the RegistrationManager that allows me to add
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a student to a course. And this, in turn, means
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that both Course and CourseOffering should provide a way to
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add a student. And therefore, I add this corresponding operation
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to the RegistrationManager, to the Course, and to the CourseOffering.
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So after doing that we will continue and populate in
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a similar way, the other classes in the system. So
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let me recap. Now we saw how to identify classes.
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How to identify members of the classes, and
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particular attributes, and operations. There is one thing that
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we're missing, a very important aspect of the
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class diagram which is the relationships between these classes.
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