Using shared pointers in map

Question

I'm trying to decide what is best choice to use in my HW. I have a map (I coded it) that supposed to store integer id's as keys and shared pointer of class named fan as values:

Map<Id, shared_ptr<Fan>> Online_list;

what is better to use shared_ptr<Fan>& or none reference ?

My homework is about creating server like Facebook with fans to be on-line and offline,so im having two maps one called Online_list and other is Offline_list, so when fan is disconnected i need to remove him from on-line list and add him to offline list.

Answer 1

A shared_ptr is a sort of reference. A pointer with memory management. You can store the plain shared_ptr since the internal refers to the same data anyway(Copy constructor increment reference count, etc).

Answer 2

Usually it's best to not store a pointer at all, but just store the Fan object by-value. Does it really make sense for two things to own this Fan object?

However, assuming that your design is correct, then you should simply store the shared_ptr by-value.