Hi there, I have learned the principles of OOP and implementations in both java and C++ either on my own or in my school courses but we only grazed it. At this point, I feel very uncomfortable with OOP and I need a good resource that will provide me with a great deal of problems that require OOP to solve (or are best solved using object oriented approaches), and their respective answers with clean code and good practices. I have had very very little practice with OOP and want to practice as much as possible to get comfortable with it. I have been searching a lot but I can't seem to find a good resource. Optimally, I would like it to begin with very trivial questions and progressively become more and more difficult. Thank you.