Need help with vector

[niceprogrammer123]

Write your question here.

class CollegeStudent { 
 public: 
 string get_name(); 
 virtual void take_test() = 0; 
 virtual string play_sports() = 0; 
 protected: 
 string name; 
}; 
class TrojanStudent : public CollegeStudent { 
 public: 
 void take_test() { cout << "Got an A."; } 
 string play_sports(){return string("WIN!");} 
}; 
class BruinStudent : public CollegeStudent { 
 public: 
 void take_test() { cout << "Uh..uh..C-."; } 
 string play_sports(){return string("LOSE");} 
}; 
int main() { 
 vector<CollegeStudent *> mylist; 
 mylist.push_back(new TrojanStudent()); 
 mylist.push_back(new BruinStudent());
  .... 

I am not sure why my instructor wrote vector<CollegeStudent *> mylist. COuld anyone explain? Thanks

[keskiverto]

Can you answer yourself any of these:

What was the topic of the lesson?
What is the purpose of the virtual?
What are inheritance and polymorphism?
What is object slicing?

[niceprogrammer123]

The topic is about polymorphism. it seems strange to me when the content of the vector points to the address. I didn't use it more often. This is what I understands with my limit knowledge

[keskiverto]

Vector holds elements of some type. Vector allocates memory for storing those elements. The size per element is fixed.

If you have a CollegeStudent in an element, that is what you have. You cannot assign TrojanStudennt to that space.

If you have a pointer in an element, it does not matter how big object it is pointing to. Additionally, copying pointers is much cheaper than copying complex objects.