Let me first make a suggestion. First, understand, yourself, what OO really means at a deep level. It is not, fundamentally, about inheritance, and when inheritance is employed it should be done so that all subclasses of a given class have exactly the same interface with no additional public methods. To break this rule introduces entropy into the program, ...


If you're looking for AP Computer Science A-level object stuff, Greenfoot is excellent. It's an OO game-design environment created specifically for teaching about OO. It's free (though there is a textbook that can be quite helpful), and there is a large teacher community that regularly posts new labs and assignments.


On this page are three textbooks. You want the 3rd one: C++/Fortran. It has a section with programming projects. These should be doable (in any OO language) after 1 or 2 semesters of programming, and should take students definitely 1 or 2 weeks of work.

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