Answer 1

Stock management
That is the only work for it. Suppose you are in an organisation and you are the in charge of keeping the track of goods in the organization.
What you as a programmer will do?Will you write down everything in a register? No,you will make a program using files. Store the data into file , manipulate it as you want.Add the recods of incoming goods and delete the data of the outgoing goods.

If you want codes then you search Google. You will get codes related to only files. There is no simple code to stock management program.

And one more thing ... keep the challenges coming! 😜