Uses case fundamentally has two kinds: business use case & system use case. Both have same way of presentation and almost same templates. If you have wrote use cases more towards to defines yours system or in other words interaction between different systems or interaction with system and human then they are more towards system use case. (e.g presenting available menus and their interaction). Business use cases are more towards to define business (e.g presenting available menu and their broad view of features) You should take another try to search material into web, lots of material available

Akash

Class A only needs to have a method AddToList. I am visualizing from example that List is going to contain only pointer of Class A. Then base class object can point derived class object so basically this method not need to make virtual. Even though if list is going to have copy of object then need to implement copy constructor & assignment operator in each derived class to make appropriate copy. But from my point of view class responsibilities should not be mixed up it should be some controller class responsibility to collect object in list rather then Class A itself. So writing a separate method in any other class is better from design-wise. Or make a another class derived by CList and create a method e.g say: "CollectDataInList(A *a)" or have this method in class which is containing CList object.

Akash

Just explanaing further.. Toy example is Aggregation. As Toy instance is created out side the scope of Class Boy. So deletion of object of Boy will not make impact of object of Toy. Bank has composition relationship with BankBranch. Since instances of BankBranch created inside scop of class Bank so if object of Bank goes out of scope then objects of BankBranch will be get deleted (destructor of Bank must be delete objects of BankBranch)

Akash