implementation of composition and aggregation in C#? [closed]

Answer 1

Well, in a garbage collected world where all objects are accessed via references, the subtle difference (in ownership) between strict composition and aggregation blurs a little - so in general (when using classes) it boils down to a field for the other object or collection:

class Building {
    private readonly List rooms = new List();
    public IList Rooms {get {return rooms;}}

    public Address Address {get;set;}
    //...
}
class Address {
    public string Line1 {get;set;}
    public string PostCode {get;set;}
    //...
}
class Room {
    public string Name {get;set;}
    public int Capacity {get;set;}
    //...
}

If I've missed the point, please clarify...

Things are more involved when you discuss structs - but generally when talking about OO concepts, struct usage is limited to value fields...