Question

I don’t understand something about push_back.

When I use push_back on an object , does it copy all its elements using the object’s
copy constructor? (what if the object doesn’t have copy constructor?)

another question:

vector<Course*> cs;
Course* c = new CScourse(); //CScourse inherits Course
cs.push_back(c);

if I use

delete c;

would it delete what I just pushed into the vector?

Answer 1

Yes every objects are copied in a vector. If the vector has to grow, each element will be copied to the new location. In your case, you are storing pointers to Course so only the pointers get copied, the actual objects remain the same.

If you delete c;, it will indeed delete the object pointed to by c that you pushed in your vector. The vector will still contain a pointer to the object that was c though, this is considered a dangling pointer. You would usually remove it from your vector before deleting it.