Explain the diamond problem Diamond problem

Q:Implement a Int function F that calculates the sum of positive values less than 1000 multiples of 3 and positive values less than 1000 multiples of 5. Q:Given a file list of files, implement a function that returns the name of the earliest modified file, owned by the administrator, executable and with a size smaller than 14*220. If no file matches the requirement, it shall return “NO FILES” Q:Data packets are received from 3 different channels. The packets must reach two objects that handle several aspects of a process. How would you design the class hierarchy and create/initialize the objects so it fulfills the requisiste? Q:What does the Visitor pattern do? What is it useful for? What principle of software design does it comply with? What are the advantages of using design patterns? Q:Imagine you have a class that represents the configuration of a device. You have to read and save this configuration to disk. You also have to send it through a REST API to the server and show it on a screen. What would be your approach to this design? Can you implement a skeleton version of it? Have you applied any design principle? Q:Imagine you have a class that controls the state machine of a device. You need to connect an RFID reader to this device and integrate its driver. You’ve been told that there’s a chance that in 6 months from now the model of the RFID reader will change. How would you design the class hierarchy so the future change is smooth and painless? What can you say about the unit testability of your design?