Is it necessary to initialize a private list class member in a constructor?

Question

I have a header file:

class day
{
public:
day(int id);
~day();

private:
int id;
std::list<meeting*> meetings;


};

and in my .cpp file:

#include "day.h"
#include "meeting.h"

day::day(int id) : id(id) {  }

Is it necessary to add meetings() to the constructor's initialization list?

day::day(int id) : id(id), meetings() {  }

I am not sure about the rules of initializing objects with constructors. Are all private members objects get initialized even if not explicitly initialized in the constructor? Also, do I need to create a destructor for the list to delete the objects in the list?

Thanks.

Answer 1

No, types that have default constructors are value-initialized by default.

If you ommit id from the initialization list, it won't be initialized, because it's an int. However, the std::list member will.

It has nothing to do with public/private.

Also, do i need to create a destructor for the list to delete the objects in the list ?

Only if day is the owner of those objects. If they are created outside of the class, and just inserted in the class' member, it's likely that the calling context has to handle the destruction.